This is to certify that this dissertation work titled

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THE COMPARISON OF DINOPROSTONE GEL AND FOLEY’S CATHETER FOR THE INDUCTION OF LABOUR

THESIS

SUBMITTED IN PARTIAL FULFILLMENT OF THE REGULATIONS OF OF THE TAMIL NADU DR. M.G.R. MEDICAL UNIVERSITY

FOR THE AWARD OF THE DEGREE

M.S. (BRANCH – II) OBSTETRICS AND GYNAECOLOGY REG.NO:221716652

OF THE

GOVERNMENT THENI MEDICAL COLLEGE AND HOSPITAL, THENI, TAMIL NADU (INDIA)

MAY 2020

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CERTIFICATE I

This is to certify that this dissertation entitled “THE COMPARISON OF DINOPROSTONE GEL AND FOLEY’S CATHETER FOR INDUCTION OF LABOUR” is a bonafide and original work done by Dr. C. Divya, post- graduate student, under my overall supervision and guidance in the department of Obstetrics & Gynaecology, Government Theni Medical College & Hospital, Theni, in partial fulfillment of the regulations of The Tamil Nadu Dr. M.G.R.

Medical University for the award of degree of M.S. Obstetrics & Gynaecology

Dr.B.SHANTHIRANI M.D DGO Professor and Head

Department of Obstetrics & Gynaecology GTMCH, Theni

Tamil Nadu

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CERTIFICATE II

This is to certify that this dissertation entitled “THE COMPARISON OF DINOPROSTONE GEL AND FOLEY’S CATHETER FOR INDUCTION OF LABOUR” is a bonafide and original research work done by Dr. C. Divya, REG.NO.221716652 department of Obstetrics & Gynaecology, Government Theni Medical College & Hospital, Theni, in partial fulfillment of the regulations of The Tamil Nadu Dr. M.G.R. Medical University for the award of degree of M.S.

Obstetrics & Gynaecology.

Date:

Place: Theni

PROF.Dr. K.RAJENDRAN M.S D.ORTHO Dean, GTMCH

Theni, Tamil Nadu

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CERTIFICATE BY THE GUIDE

This is to certify that this dissertation entitled “THE COMPARISON OF DINOPROSTONE GEL AND FOLEY’S CATHETER FOR INDUCTION OF LABOUR” is a bonafide and original work done by Dr. C. Divya, REG.NO.221716652 post-graduate student, under my direct supervision and guidance Dr.M.Thangamani,M.D.,DGO., Dr.Shanthivabala,M.D.,OG., in the department of Obstetrics & Gynaecology, Government Theni Medical College & Hospital, Theni, in partial fulfillment of the regulations of The Tamil Nadu Dr. M.G.R. Medical University for the award of degree of M.S. Obstetrics & Gynaecology (Branch – II).

Date: Signature of Guide

Place:

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DECLARATION

I, Dr. C. Divya, solemnly declare that this dissertation “THE COMPARISON OF DINOPROSTONE INTRACERVICAL GEL (CERVIPRIME) AND FOLEY’S CATHETER FOR INDUCTION OF LABOUR” is a bonafide work done by me at the Department of Obstetrics &

Gynaecology, Government Theni Medical College & Hospital, Theni, under the guidance and supervision of Dr.Thangamani , MD, DGO, Professor Department of Obstetrics & Gynaecology, Government Theni Medical College & Hospital, Theni. I also declare that this original work or a part of this work was not submitted by me or any other for any award, degree, diploma to any other university board either in India or abroad.

This dissertation is submitted to The Tamil Nadu Dr. M.G.R. Medical University in partial fulfillment of the University regulations for the award of degree of M.S Obstetrics & Gynaecology examinations to be held in May-2020.

Place: THENI Tamil Nadu Signature of the candidate

Date: (Dr. C. Divya)

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ACKNOWLEDGEMENT

It gives me immense pleasure to acknowledge one and all that in one way or the other have provided me with assistance in the successful completion of this work.

First and foremost, I thank the almighty God for all the blessings bestowed and for the strength to be perseverant and guidance to carry my work properly.

I thank my guide Dr.,Thangamani M.D. DGO, Professor, Department of Obstetrics & Gynaecology, GTMCH, Theni, Tamil Nadu, with whose knowledge, support and guidance, this thesis was made possible. His exacting standards of professional excellence, sympathetic attitude and constructive ideas at every stage have helped me to perform this study on time.

My acknowledgement would be incomplete without thanking the subjects who participated in this study. I would also like to give special thanks to my family for their patient love, unflagging belief, and dedication during the time of doing thesis and throughout my life.

Last but not the least, I thank all faculty and residents of the Department of Obstetrics & Gynaecology, GTMCH, Theni, friends and well-wishers for their encouragement in completing my study and their moral support during tough times.

October, 2019 Dr. C. Divya

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IOL is indicated when the benefits to either the mother or the fetus outweigh those of continuing the pregnancy. The American College of Obstetricians and Gynaecologists (ACOG) does not support elective induction, except for logistical reasons such as risk of rapid labour, in women living far away from the hospital, or for psycho-social indications.

IOL has two important components: cervical ripening and stimulation of uterine contractions, to achieve dilatation of the cervix and delivery of the fetus. The purpose of induction is to achieve vaginal delivery and to avoid operative delivery by Caesarean-section. It is well recognized that the success of IOL, which ultimately aims at achieving vaginal delivery, depends to a great extent on the favorability of the cervix or its readiness to go into labour. Agents used for cervical ripening may lead in the establishment of contractions to women with an unfavorable cervix.

Labour induction may also be more cost-effective and be associated with improved maternal and fetal outcomes compared with expectant management.

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3 INDUCTION OF LABOUR

Pharmacological methods like prostaglandins (PGs), and mechanical methods like membrane stripping, trans-cervical catheter, hygroscopic cervical dilators, etc. are available for pre-induction cervical ripening.

Prostaglandins

PGs have been well established as the most effective inducing agents when the cervix is unripe. PGs at low doses elicit cervical ripening even in the absence of uterine contractility. PG-E2 increases collagenase activity in the cervix and increases the levels of elastase, glycosaminoglycan, dermatan sulphate and hyaluronic acid. PGs also increase intra-cellular calcium levels, which cause contraction of the myometrial muscle, facilitating the relaxation and dilatation of cervix.

Post-dated pregnancy is defined as pregnancy continuing beyond 40 completed weeks (280 days) of gestation. Incidence is about 7.5% in the Indian population. The most frequent cause is an error in dating.

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In the present study, we compared the efficacy and safety of dinoprostone intracervical gel (cerviprime) with that of Foley’s catheter in post-dated pregnancies. Several studies in women induced at term with a Bishop score of less than 4 have demonstrated that the pessary achieved a significantly higher rate of spontaneous vaginal delivery.

Foley’s Catheter

An 18 size Foley’s catheter must be introduced through the cervix into the extra-amniotic space using a sterile technique with the aid of speculum and sponge-holding forceps. The balloon of the catheter is then inflated with 60 mL of distilled water using a syringe. The balloon must be pulled up to internal os the hanging end of the catheter is taped with the thigh.

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5 REVIEW OF LITERATURE

Humans, for centuries, have found reasons to interfere with the natural process of pregnancy by trying to hasten its outcome. This often consisted of negative attempts to abort unwanted pregnancies (without knowing the associated risks), but other more positive motives arose from the desire to relieve the mother of a life-threatening pregnancy-associated complication or to achieve more favorable delivery of a small premature baby through a constricted birth canal. Over time, a better perspective of fetal and maternal risks developed alongside more efficient methods of labour induction, and the indications shifted more commonly to serve the interests of the fetus perceived to be under risk.

The first technique to be used widely in obstetric practice was amniotomy – artificial rupture of membranes (ARM). Although it had been employed earlier, its description in medical literature could be traced back to the year 1756, when it was first used by an English obstetrician, Thomas Denman (1) who spoke highly of the process and wrote extolling its virtues.

Another mechanical method that was first mentioned by Robert Barnes, used a hydrostatic bag placed through the cervix and filled with water with a view to induce labour. Modern obstetricians following the

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same principle using a Foley’s catheter, but is well established by now that the reason behind utilization of such a mechanical method was the local release of PGs.

oxytocin has been used for labour augmentation in cases of uterine inertia, first use reported by Theobald in 1952.

PGs were first isolated from seminal fluid of monkeys, sheep, goat by Ulf von Euler at the Koralinska institute in Stockholm in 1935. Elias Corey synthesized dinoprostone in 1970 at the Harvard University.

Bergstrom, Samuelson and Vane jointly received the 1982 Nobel Prize for their discovery of PGs.

A study conducted by Facchinetti et. al. (2012) in the department of OG, Italy, comparing two dinoprostone vaginal preparations for IOL beyond 290 days of pregnancy (2). Findings showed a reduction in the number of C-sections being conducted and a concurrent reduction in the induction to delivery interval of the pregnancy, in pregnancies induced with vaginal inserts.

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A retrospective study conducted by Zhao et. al. (2016) in the department of OG, China, studied the rates of vaginal delivery among women who underwent labour induction with dinoprostone (PG-E2) vaginal insert (3). Findings suggested a vaginal delivery rate of 76.09%

when dinoprostone vaginal insert was used for IOL versus the overall annual vaginal delivery rate of 65.1% in China, during 2014. This study enabled us to better understand the efficacy of dinoprostone and the potential predictors of vaginal delivery in dinoprostone-induced labour, which may be helpful to guide the clinical use of dinoprostone, and therefore, provide better clinical services.

A prospective randomized control study conducted by Zoncanato et.

al. (2011) in the department of OG, Italy, for comparing pain associated with vaginal dinoprostone pessary versus dinoprostone gel for IOL in nulliparous women with an unfavorable cervix (4). The authors concluded that both the induction procedures should be considered equivalent since they were equally effective in ripening the cervix and initiation of labour.

However, the low Bishop’s score (≤4) should be considered a guide in determining the utility of the controlled-release preparation of

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dinoprostone since it reduces pain, thereby improving the physical and overall well-being of the patient.

A study conducted by Triglia et. al. (2010) in the department of OG, Italy, compared the efficacy of dinoprostone vaginal gel and vaginal insert for IOL (5). In conclusion, both the preparations of dinoprostone vaginal pessary and the gel appeared to be equally safe in women who were induced at full-term with a Bishop’s score <4, the use of vaginal pessary was associated with a significantly higher rate of spontaneous vaginal delivery.

Summary of Prior Publications

1. Comparative Study of Intra-cervical Foleys Catheter Instillation vs PGE2 Gel for Induction of Labour (6).

Dr. Richa Jha, Dr. Renu Rohatgi, Department of Obstetrics and Gynaecology, Nalanda Medical College and Hospital, Patna, India.

Methods: A randomized comparative study was conducted in the

department of OG, Nalanda medical college and hospital, Patna, for the period of January 2016 to January 2017. A total of 100 full-term pregnant patients with a Bishop's score ≤3, and with various indications for IOL

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were randomly allocated to receive intra-cervical Foley's catheter (50 patients) or PG-E2 gel (50 patients). After 6 hours post-induction, Bishop's score was noted and labour was augmented, if required. Results: The two groups were comparable with respect to maternal age, gestational age, indication for induction, and the initial Bishop's score. Both the groups showed a significant change in the Bishop's score post-induction of 5.10±1.55 and 5.14±1.60 for Foley's catheter and PG-E2 gel, respectively (p < 0.001). However, no significant difference was observed between the two groups in the side effect profile, rates resorting to C-section, APGAR scores, or the NICU admissions of the neonate. The induction to delivery interval was 16.01+5.50 hours in the Foley’s catheter cohort while it was 16.8+3.8 hours in the PG-E2 cohort. Conclusion: The study concluded that both intra-cervical Foley’s catheter and PG-E2 gel were considered equally effective for cervical ripening.

2. Increased risk of cervical canal infections with intracervical Foley catheter (7).

Siddiqui S, Zuberi NF, Zafar A, Qureshi RN, Department of Obstetrics and Gynaecology, Aga Khan University, Karachi, Pakistan.

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Methods: This comparative study was conducted in the department of OG

at the Aga Khan University, Karachi, between June 1 and August 31, 2002.

Cervical swabs were taken for culture and sensitivity testing prior to insertion and after spontaneous expulsion of removal of Foley’s catheter which was used to induce labour in 45 full-term women undergoing cervical ripening.

Results: Intra-cervical Foley’s catheter was retained for a mean duration

of 8.1±1.7 hours in the subjects. There was a significant change in the pathogenic microflora (0% vs 16.3%; p = 0.016) in the cervical swab cultures grown from pre-Foley’s catheter insertion as compared to the post- Foley’s catheter removal/expulsion. Various pathogenic organisms were isolated which included: β-hemolytic Streptococcus group-B, Candida albicans, Candida glabrata, and Gardnerella vaginalis. One woman (2.2%) developed fever following the insertion of intra-cervical Foley’s catheter.

Conclusion: IOL at term with Foley’s catheter is associated with a

significant increase in intra-cervical pathogen growth despite undertaking routine aseptic measures. Extreme aseptic measures should be advocated, if this is the considered the method of choice at your center, during insertion of the catheter to avoid maternal, and possible neonatal infections.

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3. Complications of trans-cervical Foley catheter for labor induction among 1,083 women (8).

Maslovitz S, Lessing JB, Many A. Department of Obstetrics and Gynaecology, Lis Maternity Hospital, Tel Aviv, Israel.

Methods: This retrospective descriptive study (2010) of 1,083 women who

underwent IOL with trans-cervical Foley’s catheter with cervical ripening done by extra-amniotic saline infusion (EASI). The primary outcome of the study was the appearance/profiling of side effects associated with the procedure.

Results: In 95 of the 1,083 women (8.8%), the balloon had to be removed

due to complications such as, acute transient febrile reaction (32/95), non- reassuring fetal heart rate tracing (22/95), vaginal bleeding (20/95), unbearable pain necessitating removal of Foley’s catheter (19/95) and altered fetal presentation: vertex to breech (14/95).

Conclusion: Complications associated with trans-cervical ripening and EASI occurred in 7.6% of the subjects and included acute febrile reaction, pain, vaginal bleeding and altered fetal presentation.

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12 INDICATIONS FOR IOL

1. High-risk pregnancies with maternal as well as fetal risks:

• Pre-eclampsia and eclampsia

• Renal disease complicating pregnancy

• Pre-mature rupture of membranes and chorio-amnionitis

2. Increased maternal risk, if termination is not advocated:

• Intra-uterine death (IUD)

• Abruptio placenta

3. Increased fetal risk:

• Post-term pregnancy

• Chronic placental insufficiency

• Rh-isoimmunization

• Maternal diabetes complicating pregnancy

• Previous unexplained still-births

• Intra-uterine growth restriction (IUGR)

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• Anomalous baby

CONTRAINDICATIONS FOR IOL

• Abnormal fetal presentation: vertex, breech, etc.

• Suspected cephalo-pelvic disproportion/contracted pelvis

• Umbilical cord presentation

• Severe IUGR with signs of fetal compromise

• Previous classical C-section

• Previous myomectomy scar

Absolute contraindications for IOL include:

• Placenta previa

• Vasa praevia

• Active maternal genital herpes

• Invasive carcinoma cervix

• Previous uterine surgery or uterine rupture

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Relative contraindications for IOL include:

• Grand multi-para

• Maternal heart disease

• Abnormal fetal heart rate pattern

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PRE-INDUCTION CERVICAL RIPENING

The status of the cervix is very significant to the success of IOL, using any method. Cervical ripening is the process by which the cervix becomes soft, compliant and partially dilated. It is a fundamental process that must occur, if delivery is to progress smoothly. Cervical ripening occurs due to a multitude of biochemical, endocrine, mechanical and possibly inflammatory events occurring simultaneously.

Cervical scoring was first described by Bishop in 1964 (9), outlined below.

Total possible Bishop’s score is 13 (10). A score of ≥9 conveys a highly likelihood for a successful induction or imminent labour. For research purposes, a Bishop’s score of ≤4 identifies an unfavorable cervix and may be an indication for cervical ripening.

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Various modifications of the Bishop’s score have since been suggested and the most widely and frequently used modification is Calder’s Modified Bishop’s Score (1974), outlined below.

It is believed that the increasing myometrial contractility, in the form of Braxton-Hicks contraction seen with advancing gestation plays a vital role in the effacement of cervix, prior to the actual commencement of labour.

PRE-REQUISITES FOR IOL

Maternal and fetal risk-benefit analysis should be done before IOL. The following may be considered as pre-requisites for IOL:

• Establishing the indication for IOL

• Informed consent

• Maternal pelvis assessment

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• Confirmation of gestational age

• Fetal weight and presentation

• Confirm lung maturity

• Cervix status assessment – success of induction and outcome

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PHYSIOLOGY OF CERVICAL RIPENING

Structurally, the cervix is mainly composed of collagen, as opposed to the myometrium, which predominantly consists of smooth muscle.

There are 4 types of collagen in the human body: collagen I, II, III, and IV.

The cervix is predominantly composed of type I (66%) and III (33%). The firmness of the cervix in the non-pregnant state is mainly due to the properties of these collagen fibrils. These bundles in turn are embedded in ground substance consisting of proteoglycans. The proteoglycans are made of a central core of proteins which are linked to proteoglycans, which are repeating disaccharide units composed of a hexosamine and a uronic acid residue.

In the cervix, the main glycosaminoglycans are dermatan sulphate and chondroitin sulphate, both of which are highly negatively charged and hydrophobic. Hence, they repel water and are responsible for firmness of cervix. Moreover, by interacting with the central protein core as well as among themselves, glycosaminoglycans facilitate the optimum orientation of the collagen fibrils, enhancing the mechanical strength of the cervix.

Towards term, the glycosaminoglycan concentration alters and the dermatan and the chondroitin sulphate are replaced by hyaluronic acid, which has different physicochemical properties.

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Hyaluronic acid is hydrophilic and imbibes water. Accumulation of water within the substance of cervix destabilizes the collagen fibrils, contributing to cervical ripening. The water content of cervix increases from 80 percent in the non-pregnant state to 86 percent in late pregnancy (Uldbjerg et. al. 1983, Liggins 1978). The accumulation of water in between the collagen fibrils has a scattering or dispersing effect, resulting in reduced mechanical strength.

Collagenase and leucocyte elastase levels are found to increase with advancing gestation and are associated with progressive decline in the concentration of cervical collagen (Uldbjerg et al 1983b).

The mature collagen which has many cross links that are responsible for its tensile strength is replaced by an immature collagen which has a few cross links.

Ganstrom et. al. have shown that the insufficient remodeling of collagen during pregnancy is an independent factor that results in labour.

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Physiological of Cervical Ripening Progressive Increase in

Gestation

Increase in Cervical Hyaluronidase and Decreased

Collagenase Inhibitors

Down Regulation of Estrogen and Progesterone Receptors

Increased Interleukin-8 and Interleukin-1B

Stimulates Collagenase and Neutrophilic Chemostaxis

Enzymatic Degradation of Extracellular Matrix

Increased Water Content

Decreased Collagen Concentration and Structural

Rearrangement

Alteration Of Proteoglycans &

Glycosaminoglycans Ratio

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21 METHODS OF INDUCTION

There has often been an attempt to make a distinction between women who are undergoing cervical ripening and women who are being formally induced for labour. This tendency is artificial as, in all, the intention is to artificially stimulate the onset of labour.

Women undergoing cervical ripening are simply those in whom there is an unfavorable cervix and where the indication allows the greater time expected for induction to establish active labour.

As the first stage of labour is a seamless progression from the latent phase into the active phase, so induction is a progression from cervical ripening through to the onset of contractions.

Agents used for cervical ripening may lead to the establishment of contractions in women with an unfavorable cervix. Many agents can be used in women with high as well as low cervical scores, but with a different expectation of the time before delivery will be achieved. The following are the methods used for induction.

• Natural methods

o Nipple stimulation o Sexual intercourse o Enema

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• Mechanical methods

o Stripping of membranes - It is an old method of inducing labour described by Hamilton in 1810. McColgin et. al. reported that two-thirds of women who underwent membrane stripping entered spontaneous labour within 72 hours. The procedure of membrane stripping causes an increase in the levels of PG-F2α.

Bouvelain et. al. showed that sweeping the membranes as a routine process at term reduced the chances of pregnancy progressing beyond 41 weeks and also reduces the need for IOL from 36 to 21%.

o Balloon catheters – Intrauterine extra-amniotic Foley’s catheter with bulbi inflation to 30 ml-rapid improvement in Bishop scores and short labours(Sherman and Colleagues 1996). Bujold et. al.

reported a lower incidence of success when IOL was done using Foley’s catheter when compared with that by oxytocin (56 vs 78%).

o Laminaria tents

o Synthetic osmotic dilators – Extra-Amniotic Saline Infusion (EASI) - Guinn and co-workers reported a longer induction to delivery interval with cervical dilators + oxytocin compared with

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that of EASI + oxytocin. The use of hygroscopic dilators appears to be safe, although anaphylaxis has followed laminaria insertion.

The attraction of dilators is their low cost and ease of placement and removal.

o Amniotomy

• Pharmacological methods – Drugs commonly used are:

o Oxytocin o Prostaglandins

As mechanical methods are believed to facilitate ripening by causing local release of PGs, their use has been superseded by administration of local PGs in most units.

PROSTAGLANDINS

Historical Milestones in the Development of Prostaglandins

Kurzork & Leib discovered biological aspects of PGs in 1930 followed by coinage and usage of the term Prostaglandins by Von Euler in 1935 for these biological molecules. About 24 years later in 1959, the origin of PGs was traced to the seminal vesicles by Elaison as these were believed to originate from prostate and seminal vesicles in the male reproductive system. Five years hence, in 1964, Bergstron elucidated the

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molecular structure of PGs which opened the realm to the vast world of PGs. PGs are derivatives of prostanoic acid. They are biologically active derivatives of 20-carbon atom poly-unsaturated essential fatty acids that are synthesized from the cell membrane. In 1966, Dr. Sultan Karim reported presence of PGs in the amniotic fluid and used semen to augment labour. Four years later, Dr. Karim established and utilized IV PG-F2α for 1st and 2nd trimester abortions.

PGs are metabolized in the liver and are excreted through the kidneys. PGs have varied actions depending upon the tissue and type of PG. The probable mechanism of action is alteration of membrane-bound calcium by inhibiting adenyl cyclase and decreasing the level of intracellular cyclic AMP. The physiological role of prostaglandins in female reproductive tract are ovulation, sperm transport, luteolysis, menstruation, and initiation and progression of labour. Below is the chemical structure of PG-E2.

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PGs are believed to induce cervical ripening by producing vasodilatation of the cervical blood vessels thereby increasing extravasation of neutrophils. The extravasated neutrophils then degranulate and release large quantities of collagenases and proteases which degrade cervical collagen and soften the structure of the cervix.

PGs act synergistically with interleukin-8 (IL-8) naturally produced in the body to stimulate the fibroblasts to produce hyaluronic acid which, in turn, alters the composition and structure of the cervix. This combined effect of PGs and ILs on the cervix along with utero-tonic effects of PGs and other utero-tonics on the uterus enables the cervix to efface and dilate during labour to allow parturition.

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26 Modes of Administration

• Intramuscular

• Intravenous

• Oral

• Vaginal

• Rectal

• Sublingual

Uses of PGs:

• Medical abortion

• Cervical ripening before surgical abortion

• Induction of labour

• In prevention and treatment of postpartum hemorrhage Other uses of PGs:

• Peptic ulcer

• To maintain patency of ductus arteriosus

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27 Contraindications:

Absolute:

• Hypersensitivity

• Asthma

• Uterine scar Relative:

• Hypertension

• CVS disorders

• Renal disease

• Liver disease

• Glaucoma Side effects:

• Fever

• Nausea, vomiting

• Diarrhea

• Bronchospasm

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• Uterine hyper-stimulation

Commonly used prostaglandins are

• Prostaglandin E1 (Misoprostol)

• Prostaglandin E2

• Prostaglandin F2α

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29 Mechanism of Action of Prostaglandins

Muscle physiology consists of three phases:

• Phasic contraction

• Tonic tension

• Relaxation

Phasic contraction is intermittent and may last for a short or long period of time, whereas tonic tension is fairly constant, lasting for prolonged periods. At the myometrial cellular level, PGs have been found to induce both phasic contractions as well as tonic tension with superimposed phasic contractions. In practical terms, they increase both the resting tone of the uterine myometrium, as well as the amplitude and duration (making the contractions stronger and last longer) of the myometrial contractions.

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At a molecular level, phasic contractions are due to influx of Sodium ions (Na+) into the myometrial cell, whereas tonic tension is due to increased availability of intra-cellular calcium (Ca2+). Both these processes are affected by PGs.

PGs induce the formation of gap-junctions between the myometrial cells, which help in the development of co-ordinated myometrial action, giving the advantage of a functional syncytium.

Anti-PG substances, like indomethacin, are used in the management of pre-term labour. They inhibit the formation of gap-junctions, apart from inhibiting the movement of Na+ and Ca2+ to/from the cells. Moreover, by inhibiting the actions of the enzyme cyclo-oxygenase, they divert the arachidonic acid metabolism through the lipo-oxygenase pathway. This leads to the production of leukotrienes instead of PGs. Leukotrienes have minimum direct effect on human myometrial contractility.

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31 CERVICAL RIPENING

The cervix plays a dual role in human reproduction during pregnancy. It should remain firm and closed allowing the fetus to grow in- utero until functional maturity is attained. During labour, it should soften and dilate allowing the fetus to pass through the birth canal. The process by which the cervix becomes soft, compliant and partially dilated is termed cervical ripening.

It is widely believed that PGs constitute the final common pathway responsible for the onset of labour. They are potent agents and can cause both myometrial contractions as well as cervical ripening. An increase in the levels of PGs at the onset of labour has been demonstrated in all mammals, including humans. Levels of PGs and their metabolites have been found to increase in amniotic fluid in advanced labour. Therefore, it could be deduced that they are essential for the onset of labour.

PGs have been used to induce labour since 1960. Intra-cervical PGs as gel preparation have been widely used and studied.

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32 OXYTOCIN

In modern obstetric practice, oxytocin is more commonly used in combination with amniotomy making it unsuitable for use in women who have cervical scores below 6.

When compared to induction with PGs, evidence suggests that oxytocin induction is associated with a lower chance of delivery within 24 hrs. In women with an unfavorable cervix, induction with oxytocin was associated with higher rates of C-section.

Lower dose regimens are recommended with starting doses of 1-2 mU/min, increased at intervals of 30 minutes or greater. The maximum dose is the minimum dose needed to maintain a contraction frequency of 3-4/min or an absolute maximum of 32 mU/min.

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33 RELAXIN

Relaxin has been used both vaginally and intra-cervically to induce labour but studied have failed to show any benefit compared to PGs.

Hyaluronidase and estrogen are of historical interest only.

RU 486 OR MIFEPRISTONE

It is a derivative of 19-norprogestin-norethindrone containing a dimethyl-aminophenol substituent at the 11-beta position. It effectively competes with both progesterone and glucocorticoids for binding to their respective receptors.

This anti-progestin has been studied extensively for pre-induction cervical ripening at term.

• A 200 mg dose given orally for 2 days, 48 hrs before the formal induction. Engdman et. al. reported that mifepristone was a safe, efficient, and suitable induction agent for initiation of labour at term.

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34 AMNIOTOMY

ARM can be used to induce labour but implies a commitment to delivery. The main disadvantage of amniotomy, when used for induction, is unpredictable and occasionally long intervals to the onset of contractions.

There is an increased incidence of chorio-amnionitis and cord compression patterns with early amniotomy.

RISKS OF IOL

• Increase in rates of C-section

• Uterine hypercontractility

• Uterine hypertonus is defined as a single uterine contraction that lasted 2 or more minutes.

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Tachysystole is defined as atleast 12 contractions in 20 min.

Hyperstimulation is defined as either hypertonus or tachysystole associated with abnormal fetal heart rate (FHR) pattern.

FAILED INDUCTION

There is no universally accepted definition for failed induction.

Failed induction should be defined as inability to achieve the active phase of labour despite adequate stimulation.

In a primigravida, 8-12 hrs and in multigravida, 6-8 hrs may be considered as a reasonable period after adequate oxytocin stimulation to label it as failure of induction. In primigravida with an unfavorable cervix, failed induction probably occurs in 20-35% cases with IV oxytocin, and this improves to 3-5% when local PGs are used to prime the cervix prior to oxytocin.

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36 Increased C-Section Rates

The incidence of C-section following IOL is higher than in spontaneous labour. The actual incidence in induced labour varies from 15-30% in hospital practice. The indications for C-section are the following.

• Dystocia

• Abnormal uterine action

• Malposition

• Failed induction

• Fetal distress

DINOPROSTONE GEL (CERVIPRIME)

It is a PG-E2 analogue. Local application of cerviprime gel is used for cervical ripening. It is usually available as 0.5 mg gel and can be used

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both intra-vaginally and intra-cervically. It is most effective when vaginal Ph >4.5. Application should be done in or near the labour ward where uterine activity and fetal heart rate monitoring can be performed.

Contraction occurs within first 4 hrs of application and show peak activity in the first 4 hrs. If oxytocin was used for acceleration, cerviprime should be started 6-12 hrs after oxytocin.

The cerviprime gel foam is available in a 2.5 mL pre-loaded syringe for intra-cervical application. With the woman in a dorso-lithotomy position, the cervix is exposed and held. The tip of cannula, which is attached to the pre-filled syringe, is inserted gently to just below the internal os. The gel is then instilled into the cervix. The patient is kept in a reclining position for the next 30 min. The dose may be repeated every 6

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hrs depending on the response. The manufacturers recommend a maximum cumulative dose of 1.5 mg of dinoprostone within a 24-hr period. It is a good clinical practice to perform a pelvic examination and assess the state of the cervix prior to the instillation of the next dose.

After using 1.5 mg of dinoprostone in the cervix, oxytocin induction should be delayed for 6-12 hrs because the effect of PGs may be heightened with oxytocin.

Intra-cervical PG-E2 gel not only ripens the cervix but also induces labour and reduces the risk of failed induction. About 40% of women do not need further induction.

A systematic Cochrane review showed that vaginal PG-E2 compared with placebo or no treatment reduced the likelihood of vaginal delivery not being achieved within 24 hrs. The risk of the cervix remaining unfavorable or unchanged was reduced and the need for oxytocin augmentation was reduced when PG-E2 was compared to placebo. There

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was no evidence of a difference between C-section rates although the risk of uterine hyper-stimulation with the FHR changes was increased.

The review also found that the PG-E2 tablet, gel and pessary were all equally efficacious and the use of sustained release PG-E2 inserts appeared to be associated with reduced instrumental vaginal delivery rates when compared to vaginal PG-E2 gel or tablet.

The authors concluded that PG-E2 increased successful vaginal delivery rates in 24 hrs and cervical favorability with no increase in operative delivery rates. Sustained release vaginal PG-E2 was considered superior to vaginal PG-E2 gel for some outcomes studied.

Evidence suggested that oral PG-E2 may be more effective than placebo in inducing labour and reducing rates of C-section. However, no clear advantages to oral PGs over other methods of IOL could be found in other systematic reviews carried out. Oral PG consistently resulted in more frequent gastrointestinal side effects, like vomiting, compared to other treatments.

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40 FOLEY’ S CATHETER

Foley’s catheter balloon is the most commonly used mechanical device for labour induction, which acts not only as a mechanical dilator of the cervix but also a stimulator of endogenous PG release from the fetal membranes.

Double-balloon catheter has been designed and introduced recently for IOL. However, two studies showed that double-balloon catheter could not improve outcomes and might be associated with more operative deliveries compared with Foley’s catheter balloon. Compared with vaginal PG-E2 gel in term labor induction, Foley’s catheter achieved similar vaginal delivery rates, with fewer maternal and neonatal side-effects. Cost- effectiveness analysis alongside the trial showed that Foley’s catheter and PG-E2 labour induction resulted in comparable costs. In the Foley’s catheter group, the induction material was cheaper but induction to delivery interval was longer, which generated higher costs due to longer labour ward occupancy.

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To improve the efficacy of induction, different balloon inflation sizes and ripening time have been compared. Balloon inflation sizes of 30–

80 mL have been reported and two randomized controlled trials showed that larger balloon volume was associated with shorter induction to delivery interval without affecting rates for C-section. As regards the time limitation for exposure to extra-amniotic balloon, some practitioners set a maximum time limit, while others wait till the balloon catheter is spontaneously expelled. Cromi et. al. reported that shortening the maximum time for cervical ripening (from 24 to 12 hrs) might increase the proportion of women who delivered vaginally within 24 hrs after Foley’s catheter insertion.

POST-DATED AND POST-TERM PREGNANCY

Post-Dated Pregnancy

Pregnancies that last longer than the estimated date of confinement (40 wks).

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42 Post-Term Pregnancy

Pregnancies that last longer than 42 wks.

The accepted normal duration of pregnancy is 266 days after ovulation. The timing of an ovulatory event may be estimated as occurring 14 days after the first day of the last menstrual period if cycles occur at a 28-day interval, provided the cycles are regular in length.

Some physicians consider prolonged pregnancy and post-dated pregnancy to be the same entity, while others believe that the term prolonged pregnancy should be reserved for well dated pregnancies known to exceed 42 wks of gestation and that the term post-dated should be reserved for the more global group of patients for whom reliable dating criteria may not be available.

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43 Diagnosis and Incidence

The incidence of post-datism decreases as the accuracy of the dating criteria used increases. The reported incidence of postdate pregnancy ranges from 3-17%.

The advent of sensitive over-the-counter pregnancy test kits and the common use of early ultrasound for dating have improved the clinical estimation of conception in women who present early for pre-natal care.

Sonography is most useful when performed before the 20th week of gestation, with measurement of crown-rump length in the first trimester as the most accurate parameter.

Menstrual recall, early palpation of uterine size and Doppler auscultation of the FHR tones are less accurate but helpful methods used to determine the estimated date of delivery.

When menstrual dating is the prevailing criteria, the incidence of postdate pregnancy is around 8.8%. When early ultrasound corroborates

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the menstrual dating, the incidence of post-dated pregnancies falls to about 6.9%.

At a patient’s first visit, all available clinical data should be gathered and correlated to reach the best estimate of gestational age. Once an estimated date of delivery is established, it should remain unchanged by the acquisition of later or less accurate means of estimation. For instance, if a patient’s menstrual dates and first trimester sonography agree on an estimated due date, later measurements obtained by ultrasound in the third trimester should not alter that established due date.

Properly timed initiation of labour is a complex process requiring appropriate interactions of the fetal hypo-thalamo-hypophyseal-adrenal axis, the placenta, fetal membranes, deciduas, uterine myometrium, and cervix. Failure to co-ordinate these interactions impede labour, several different pathogenic mechanisms may, thus, result in post-dated pregnancy.

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Simply put, interactions between the endocrine system of the fetus, placenta and the mother must induce anatomic and functional changes in the uterine musculature and cervical resistance. The myometrium is rendered more responsive to stimulation of stretch receptors and begins to generate high frequency, high amplitude electrical signals that result in co- ordinated contractions. Once activated, the uterus is also more receptive to stimulation by PGs and oxytocin.

Cervical ripening is a metabolic process which triggers or can be triggered by the intra-uterine or fetal precursors to labour.

Complications

• Macrosomia

• Fetal asphyxia

• Meconium aspiration

• Post-maturity syndrome

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The incidence of post-term pregnancy varies, ranging from 3-14%

with an average of about 10%. The incidence of post-dated pregnancy varies depending on whether the calculation was based on the history and clinical examination alone, or whether early pregnancy ultrasound examination was used to estimate the gestational age.

Prolonged pregnancy has uncertain definition and uncertain pathophysiology. Meta-analysis of randomized control trials in IOL for prolonged pregnancy showed that decrease in the peri-natal mortality and C-section, but randomized control trials (RCT) are clinically so variable that conclusions cannot be justified. However, observational data showed that routine induction for prolonged pregnancies increased C-section deliveries and lower chances of vaginal delivery.

The 2008 SOGC guidelines for the management of post-dated pregnancy recommends routine first trimester ultrasound to reduce error in EDD estimation and reduce early induction.

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In 2003, Olesen and Westergaard in their study of peri-natal and maternal complications related to post-term delivery concluded that post- term delivery was associated with significantly increased risks of peri-natal and maternal complications like meconium aspiration, and asphyxia before, during and after delivery. There was a significantly increased risk of obstetric complications, such as PPH, cephalon-pelvic disproportion, cervical rupture, dystocia, fetal death, C-section and puerperal infection.

In 2004, Neff MJ in his article “ACOG releases guidelines on the management of post term pregnancy” stated that most cases of post-term pregnancies resulted from prolongation of gestation. Other cases were mainly due to the inability to correctly define EDD. The adverse sequel can be reduced by making accurate gestational age and diagnosis of post-term gestation as well as recognition and management of risk factors. Ante-natal surveillance and IOL were the two strategies that decreased the adverse fetal outcome.

In 2005, Donald Briscoe in his article “management of pregnancies beyond 40 weeks gestation” concluded that the number of pregnancies

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considered post-term will be decreased when early USG dating was performed.

In 2007, Chabra, Dargan, and Nasare in their study on post-dated pregnancies concluded that in women with post-dated pregnancy, an individualized approach with IOL when necessary was the proper line of management.

The historical basis for the concept of an upper limit of human pregnancy duration was the observation that peri-natal mortality increased after the expected due date was surpassed.

Pregnancy beyond due-date is one of the most frequent clinical dilemmas faced by the obstetrician and decide whether to choose expected management with ante-partum fetal surveillance or to prescribe IOL.

Remains controversial

To understand the complications of post-term pregnancies, we have to be familiar with the patho-physiological changes in these pregnancies.

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It is these patho-physiologic alterations that have an impact on ante-natal and intra-partum FHR patterns.

AMNIOTIC FLUID VOLUME

Amniotic fluid volume increases by 10 mL/wk, 400 mL at mid- pregnancy and 1000 mL at term. During the post-date period, it is estimated that there is a 33% decline in amniotic fluid volume each week. Fluid becomes milky and cloudy because of flakes of vernix caseosa. The phospholipid composition changes because of the presence of large number of lamellar bodies released from fetal lungs and L:S ratio becomes 4:1. The color of the fluid becomes green as the fetus passes meconium.

PLACENTAL CHANGES

• Reduction in the diameter of the placenta and length of chorionic villi

• Fibrinoid necrosis

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• Accelerated atherosis of chorionic and decidual vessel

• Appearance of hemorrhagic infarcts

• Placental apoptosis

ACCURATE PREGNANCY DATING

First trimester USG should be offered, ideally between 11-14 weeks, to all women as it is a more accurate assessment of gestational age than last menstrual period with fewer pregnancies prolonged past 41 weeks.

If there is a difference of >5 days between gestational age dated using the last menstrual period and first trimester USG, the estimated date of delivery should be adjusted as per the first trimester USG. If there is a difference of >10 days between gestational age dated using the last menstrual period and second trimester USG, the estimated date of delivery should be adjusted as per the second trimester USG. When there has been both a first and second trimester USG, gestational age should be determined by the first trimester ultra sound.

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Uterine tachysystole with FHR changes denoted uterine hyper- stimulation syndrome (tachysystole or hyper-systole with FHR changes such as persistent decelerations, tachycardia or decreased short term variability).

Cochrane Reviews

Sustained release pessaries in comparison with gel have not shown to significantly reduce C-section rates or improve adverse neonatal or maternal outcomes. There is seen a reduction in the use of oxytocin augmentation and the reduction in instrumental delivery rates. The frequency of vaginal examinations is reduced when using sustained release pessaries. Intra-cervical PGs are effective compared to placebo but appear inferior when compared to intravaginal PGs.

There are two meta-analyses on the efficacy of dinoprostone vaginal pessary for labor induction. Sanchez-Ramos et. al. (11) concluded that the vaginal insert was less effective than other PGs for cervical ripening and IOL, whereas the conclusion reached by Hughes et. al. (12) was that the

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vaginal insert was equally effective as other PG routes of administration in terms of delivery by 24 hrs, rate of uterine hyper-stimulation with FHR changes and C-section delivery rate. The reason for these contrasting conclusions could be the heterogeneity of included trials, in terms of outcome measures, inclusion and exclusion criteria, pre-induction Bishop’s score, demographic characteristics of the study population, and/or protocol of induction. Most vaginal pessary protocols used it for 12 hrs.

However, there is evidence that the pessary can release PGs in a linear fashion for 24 hrs and controlled-release dinoprostone is approved for 24-hr use in Europe. In a non-systematic analysis conducted in 2005 by Rath et. al. (13), the potential benefits of continuing the use of controlled- release dinoprostone for 24 hrs when 12-hr exposure has not resulted in the onset of labour was emphasized upon.

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AIM AND OBJECTIVES

• The aim of this study is to compare the efficacy of intracervical dinoprostone gel (cerviprime) with that of Foley’s catheter for pre- induction cervical ripening.

• The induction delivery interval, maternal and fetal outcomes, and the need for augmentation of labour in these two groups are to be compared

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MATERIALS AND METHODS

PERIOD OF STUDY

April 2019 to September 2019

METHODS

This prospective clinical trial was carried out in the department of OG, Theni Medical College, during the period of April to September 2019.

The purpose of this study was to compare the efficacy of Foley’s catheter with intra-cervical dinoprostone gel for pre-induction cervical ripening. The induction delivery interval, maternal and fetal outcomes, and the need for augmentation of labour in the two groups were compared.

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55 INCLUSION CRITERIA

• Term pregnant women

• Singleton pregnancy

• Cephalic presentation

• Bishop’s score <3

• Post-dated pregnancies

• Mild oligohydramnios

EXCLUSION CRITERIA

• Placenta praevia

• Malpresentations

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• Scarred uterus

• Active genital infection

• Multiple pregnancies

• Ante-partum hemorrhage

• Pre-mature rupture of membranes (PROM)

• Prolapsed umbilical cord

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57 METHODOLOGY

This study recruited 200 women who were in-patient in the labour and delivery units of Theni Medical College, Theni.

On admission, a detailed history was taken. Complete general and obstetric examination was carried out. Under strict aseptic precautions, vaginal examination was done. Bishop’s score was assessed.

Gestational age was determined by the date of the last menstrual period preceded by regular cycles and confirmed by ultrasonography in the first trimester.

Routine obstetric scan for fetal maturity and well-being was done.

Once the inclusion criteria were fulfilled, the patient was counseled and written informed consent obtained.

Of the subjects, 100 belonging to group A had dinoprostone gel instilled into endocervical canal, while the next 100 belonging to group B had Foley’s catheter insertion for induction.

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From the start of induction, uterine activity and fetal heart rate were monitored clinically. Frequency and duration of contractions were monitored by abdominal palpation. FHR was monitored once in 15 minutes during the first stage, and once in 5 minutes during the second stage. The pulse rate, BP and temperature were recorded every hour. Progress was monitored using WHO partogram. Bishop’s scores were reassessed after 6 hrs in the gel group and after 24 hrs in the Foley’s group. In cases of unfavorable cervix, gel was re-instilled after 6 hrs in gel group. A third dose of gel was instilled in case of unfavorable cervix after next 6 hours. If Bishop’s scores were more than 6, labour was augmented with oxytocin.

In case of signs of fetal distress, the subjects were taken up for C- section. Maternal and fetal outcome and complications were noted.

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STATISTICAL ANALYSIS

The information collected regarding all the selected cases were recorded in a master chart. Data analysis was done with the help of computer using Epidemiological Information Package.

Using this software, frequencies, percentage, mean, standard deviation and p-values were calculated through Student ‘t’ test for raw data and chi-square test for consolidated data. A p-value of <0.05 was taken to denote significant relationship.

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60 OBSERVATIONS & RESULTS

The present study was conducted on 200 pregnant females at term who were divided into 2 groups: IOL in the first group was done with dinoprostone gel (100 subjects); IOL in the second group was done using Foley’s catheter. The observations from our study were as follows:

1. Age

Gel group: All pregnant females were adults in the age range of 18-33 years with a mean age of 22.8 (SD ± 2.6) years and median of 23 years.

Foley’s group: All females were adults in the age range of 18-32 years with a mean age of 23.1 (SD ± 2.8) years and median of 23.5 years. The Table below shows the age distribution of the two groups.

Age Group (Years) Gel Foley’s Catheter

<20 22 25

20-25 68 63

>25 10 12

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As evident from the chart above, there was no difference in the distribution profile of the subjects between the two study groups thereby eliminating the selection bias factor.

2. Obstetrics Score

The obstetric score frequency distribution pattern was similar in both the groups of subjects. A majority of the subjects in both the groups were primigravida (69% in gel versus 65% in Foley’s group).

Obs. Score Gel Foley’s Catheter

Primi-gravida 69 65

Multi-gravida 31 35

22 68 10

25 63 12

<20 20-25 >25

AGE DISTRIBUTION COMPARISON BETWEEN THE TWO STUDY GROUPS

Gel Foley’s Catheter

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62 3. Bishop’s Score

Bishop’s score in all the 200 subjects for this study was in the range of 2-4. The mean Bishop’s score for the gel group was 2.99 (SD ± 0.46) while the mean for Foley’s group was 2.93 (SD ± 0.54). The chart below shows the frequency distribution for Bishop’s score.

69 31

65 35

PRIMI-GRAVIDA MULTI-PARA

COMPARISON OF OBSTETRICS SCORE

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63 4. Induction to Delivery Interval

The mean time interval between induction and delivery was approximately 2 hours more for subjects induced with Foley’s catheter when compared to IOL with gel. The mean induction to delivery interval for the gel group was 19.8 (SD ± 9.6) hours while it was 21.4 (SD ± 9.8) hours for the Foley’s group. The table below summarizes the frequency distribution of the induction to delivery interval for the 200 subjects.

Induction

De(Hours) Gel Foley’s Catheter

≤15 41 34

16-30 52 55

>30 07 11

11 79 10

18 71 11

2 3 4

COMPARISON OF BISHOP'S SCORE

Gel Foley catheter

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64 5. Induction Augmentation

Slightly more subjects in the Foley’s group (62%) required

administration of oxytocin for augmentation of labour when compared to those in the gel group (51%) but this was not considered statistically significant (p > 0.05).

Augmentation Gel Foley’s Catheter

Oxytocin 51 62

ARM 20 22

Additionally, 20% subjects in the gel group and 22% in the Foley’s group required ARM for augmentation of labour.

41 52 7

34 55 11

≤15 16-30 >30

INDUCTION TO DELIVERY INTERVAL(HOURS)

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65 6. Mode of Delivery

On an average, the rates of normal vaginal delivery, C-section, and instrument-assisted deliveries for subjects in both the groups, induced with dinoprostone gel and Foley’s catheter, were comparable and considered non-significant. The table below summarizes the mode of delivery used in the subjects.

Mode of Delivery Gel Foley’s Catheter

Labour Natural (LN) 54 63

Assisted Vaginal 19 15

LSCS 27 22

51 20

62 22

OXYTOCIN ARM

COMPARISON OF SUBJECTS REQUIRING LABOUR AUGMENTATION

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66 7. Maternal Complications

No maternal complications occurred in 97% of the subjects in the Foley’s group while no complications occurred in 89% of the subjects in the gel group. This difference between the 2 groups was comparable and considered statistically non-significant. Post-partum hemorrhage occurred in 11% of subjects in the gel group versus 3% in the Foley’s group. The table below summarizes the maternal complications data.

54 27 19

63 22 15

LABOUR NATURAL (LN)

C-SECTION INSTRUMENT-

ASSISTED

COMPARISON OF MODES OF DELIVERY

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67 8. Neonatal Birth Weight

There was no statistically significant difference in the birth weight of the neonate post-partum between the gel and the Foley’s groups (p > 0.05).

The table below summarizes the birth weight data.

Birth Weight (Kg) Gel Foley’s Catheter

<3 69 62

>3 31 38

11 89

3 97

POST-PARTUM HEMORRHAGE NO COMPLICATIONS

COMPARISON OF MATERNAL COMLICATION RATES

Gel Foley's Catheter

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68 9. APGAR Scores

The 1-min and 5-min APGAR scores of the neonate were compared between the two groups of subjects. The findings were not considered significant for both the APGAR scores (p > 0.05). The charts below summarize the findings.

69 31

62 38

<3 >3

COMPARISON OF NEONATAL BIRTH WEIGHT

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69

76 24

72 28

7 8

1-MIN APGAR SCORE COMPARISON

9 91

7 93

7 8

5-MIN APGAR SCORE COMPARISON

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70 10. NICU Admission Rates

The rates of shifting of neonates to NICU for post-partum care between the 2 groups were comparable (18% versus 13%) and the difference was not considered statistically significant (p > 0.05). The table below summarizes the findings. Of the 18% neonates from the gel group and 13% from the Foley’s group shifted to NICU, there were 2 neonatal deaths in the gel group and 1 in the Foley’s group.

NICU Admission Gel Foley’s Catheter

Level - I 14 12

Level - II 4 1

Nil 82 87

14 4 82

12 1 87

LEVEL - I LEVEL - II NIL

COMPARISON OF NICU ADMISSIONS POST-PARTUM

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71 DISCUSSION

IOL is one of the most common and frequently used interventions in clinical obstetrics and is a widely used method for varied indications, the most frequent being post-dated pregnancies. Whether induction would be successful is strictly based on the cervical status of the parturient, and as previously discussed, assessed using the Bishop’s/Modified Bishop’s score.

Post-dated pregnancies are pregnancies that extends beyond 40 weeks of gestation. Management of post-term pregnancies presents a challenge to the clinicians to be able to identify who needs to be induced, who would respond to induction, and who would require a C-section. Post- term pregnancies are associated with an elevated risk of fetal morbidity and mortality. Ante-partum still-birth is a major public health concern accounting for a greater contribution to perinatal mortality than deaths from complications of pre-maturity or the sudden infant death syndrome (SIDS) taken in totality. Increased neonatal mortality from post-term pregnancies could, therefore, be prevented by IOL at term. However, both clinicians and patients are concerned about the risks of IOL which include failed induction, and increased rates of C-section.

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The most common cause of prolonged pregnancy is inaccurate dating. Common risk factors include primiparity, and previous post-term pregnancy.

IOL has two important components: cervical ripening and stimulation of uterine contractions, to achieve dilatation of the cervix followed by delivery of the fetus. The purpose of induction is to achieve vaginal delivery and to avoid operative delivery by C-section. It is well recognized that the success of IOL, which ultimately aims at achieving vaginal delivery, depends to a great extent on the favorability of the cervix or its readiness to go into labour. Agents used for cervical ripening may lead to contractions in women with an unfavorable cervix.

IOL with PGs offer the advantage of promoting cervical ripening as well as myometrial contractility in women who present with premature rupture of membrane and an unfavorable cervix.

In the present study, we compared the efficacy and safety of dinoprostone intracervical gel with that of Foley’s catheter for IOL in post- dated pregnancies. Two groups of 100 subjects each were recruited for this study, qualifying all inclusion criteria, presenting to the department of OG, Government Theni Medical College, Theni, for confinement.

This is to certify that this dissertation work titled

THESIS

TABLE OF CONTENTS

AIM AND OBJECTIVES