1.Dr. N. SRAVANTHIDr. RENUKA

2. Induction of labor Implies stimulation of contractionsbefore the spontaneous onset of labor, with or withoutmembranes. Augmentation refers to stimulation of spontaneous thatare considered to be inadequate because of failed cervicaldilatation and fetal descent 3. Evaluation before induction of labour MATERNAL FETAL1. Confirm indication for induction 1. Confirm gestational age2. Review contraindications to labor2. Assess need to document fetal and/or vaginal delivery lung maturity status3. Perform clinical pelvimetry to 3. Estimate fetal weight (either by assess pelvic shape and adequacyclinical or ultrasound of bony pelvis examination)4. Determine fetal presentation and4. Assess cervical condition (assign lie Bishop score)5. Confirm fetal well-being5. Review risks, benefits and alternatives of induction of labor with patient 4. WHO RECOMMENDATIONS FOR INDUCTION OFLABOUR Induction of labour should be performed only when there is a clearmedical indication for it and the expected benefits outweigh itspotential harms.In applying the recommendations, consideration must be given tothe actual condition, wishes and preferences of each woman, withemphasis being placed on cervical status, the specific method ofinduction of labour and associated conditions such as parity andrupture of membranes. 5. Induction of labour should be performed with caution since theprocedure carries the risk of uterine hyperstimulation andrupture and fetal distress. Wherever induction of labour is carried out, facilities should beavailable for assessing maternal and fetal well-being 6. Women receiving oxytocin, misoprostol or other prostaglandinsshould never be left unattended Failed induction of labour does not necessarily indicatecaesarean section Wherever possible, induction of labour should be carried out infacilities where cesarean section can be performed 7. Indications Indicated when benefits to mother or fetus outweighsthose of continuing the pregnancy 8. ACCEPTED ABSOLUTE INDICATIONS Hypertensive disorders Fetal compromise Pre-eclampsia/eclampsia Fetal growth restriction Maternal medical conditions Isoimmunization Diabetes mellitus Non-reassuring antepartum Renal disease fetal testing Chronic pulmonary disease Oligohydramnios Pre- labor rupture of membranes Fetal demise Chorioamnionitis Prolonged pregnancy(>42weeks) 9. RELATIVE INDICATIONS Hypertensive disorders Fetal anomalies requiring Chronic hypertension specialized neonatal care Maternal medical condition Logistic factors Systemic lupus erythematosus Risk of rapid labor Gestational diabetes Distance from hospital Hypercoagulable disorders Psychosocial indications Cholestasis of pregnancy Advanced cervical dilatation Polyhydramnios Previous still birth Post term pregnancy(>41weeks) 10. CONTRAINDICATIONS ABSOLUTE RELATIVE Prior classic uterine incision or Cervical carcinomatransfundal uterine surgery Funic presentation Active genital herpes infection Malpresentation (breech) Placenta or vasa previa Umbilical cord prolapse Transverse or oblique fetal lie Absolute cephalopelvicdisproportion (as in women withpelvic deformities) 11. RELATIVE INDICATIONS Hypertensive disorders Fetal anomalies requiring Chronic hypertension specialized neonatal care Maternal medical condition Logistic factors Systemic lupus erythematosus Risk of rapid labor Gestational diabetes Distance from hospital Hypercoagulable disorders Psychosocial indications Cholestasis of pregnancy Advanced cervical dilatation Polyhydramnios Previous still birth Post term pregnancy(>41weeks) 12. CONTRAINDICATIONS ABSOLUTE RELATIVE Prior classic uterine incision or Cervical carcinomatransfundal uterine surgery Funic presentation Active genital herpes infection Malpresentation (breech) Placenta or vasa previa Umbilical cord prolapse Transverse or oblique fetal lie Absolute cephalopelvicdisproportion (as in women withpelvic deformities) 13. Risks CESAREAN DELIVERY especially increased in nulliparas two- to threefold risks rates are inversely related with favorability of the cervix at induction,that is, the Bishop score. CHORIOAMNIONITIS UTERINE ATONY Postpartum atony and hemorrhage are more common in womenundergoing induction or augmentation Intractable atony was the indication for a third of all cesareanhysterectomies 14. Cervical ripening : A prelude to the onset of labour whereby the cervixbecomes soft and compliant. This allows its shape to change from being long and closed, to being thinned out (effaced) and starting to open (dilate). It either occurs naturally or as a result of physical or pharmacological interventions NICE 2008 15. Smooth muscle Cellular FibroblastCollagen I (70%)CervixCollagen III (30%)Elastin Extra cellular ProteoglycansDecorin 16. MECHANISM INVOLVED IN CERVICAL RIPENING Cervix is a complex and heterogeneous organ, that undergoesextensive changes throughout gestation and parturition. Chronic process, which begins within the first trimester of pregnancyand progressively proceeds until term Softens, dilates and effaces the cervix This remodeling process is extremely complex and involves properly timed biochemical cascades, interaction between cellular and extra cellular components, and infiltration by inflammatory cells. 17. Hyperplasia of cellular components in early gestationphysiologic cell death, in advanced pregnancyUp gradation of-Invasion by neutrophils and macrophagesDecorin -Nitric oxide regulates MMPs and releases PGs.COLLAGEN REMODELLING 18. EnzymaticdegradationIncreased CERVICALHormonal decorinRIPENINGinfluences IncreasedHyaluronic acid 19. Extra-cellular changesDispersion and Disorganization of Collagen Collagenases, Proteases and Elastases (produced by fibroblast andPMN) MMP 1 and 8 source: stromal cells and neutrophils Proteoglycans e.g. Decorin Inflammatory cells--- increase in degradative enzymes Hyaluronic acid (GAG)- increase water content 20. Remodeling of cervixDegradative Inhibitors enzymes-Collagenases, MMP 1 & - Tissue inhibitors of8, elastases MMPs, alpha 2 macroglobulin-Source stromal cells,neutrophils andmacrophages-Activity enhanced bycytokines like IL-1B, IL-8 21. AFFECTING ELEMENTS CYTOKINES e.g. interleukin-1enhance the activity of collagenases and interleukin 8,Platelet activating factor,monocyte chemotactic factor-1 HORMONAL INFLUENCES Estrogensincreases collagenasesProgesteronesinhibit collagenases, hyaluronic acid & IL-8 NITRIC OXIDE stimulates leukocytes infiltration induce prostaglandin secretion 22. PREINDUCTION CERVICAL RIPENING The condition of the cervix influences the success of inducing labor. A cervical examination is essential before labor induction is initiated. In 1964, Bishop developed a scoring system to evaluate multiparous womenfor elective induction at term. The scoring system is based on properties of the cervix that may be assessedclinically at the time of pelvic examination such asdilatation, effacement, consistency, and position as well as the station of thefetal presenting part 23. Bishop Scoring System Used for Assessment of Inducibility DILATATION EFFACEMENTSTATION CERVICALCERVICALSCOREPOSITION (cm)(%)(3 to +2) CONSISTENCY0CLOSED 0 - 30 -3 FIRM POSTERIOR1 1-2 40 - 50-2 MEDIUMMIDPOSITION2 3-4 60 - 70-1 SOFT ANTERIOR3 >/= 5 >/=80+1, +2 -- 24. Bishop score is now widely used to predict the success oflabor induction. The higher the Bishop score, the more ripe orfavorable the cervix is for labor induction. A low Bishop score, usually considered less than or equalto 6, is unripened or unfavorable and will benefit fromcervical ripening 25. Other predictors Maternalfactors Height,FetalParity Age Fetal factors weight, BMI fibronectin Insulin like growth FactorFetal weight binding>3.5kg.proteinGestational age fFN in cervical secretions: Not more predictive than Bishops score 26. Other scoring systems Fields system Burnett modification of bishops score Weighted Bishops score by Friedman Pelvic score by LangeHowever, despite this none of the modifications have shownimproved predictability. 27. ULTRASOUND IMAGING Adv. Over digital examination: more objective and assesses the entire length ofthe cervix. Both bishops score and TVUS predicted successful induction. Bishops score predicted delivery within 24 hrs. and TVUS within 48 hrs. Cervical length related to latent phase of labor, funneling related to both latentand active phase of labor. (Am. J of Obs. Gynecol. 1994;171.) Some other studies have not found any USG parameter predictive, and considerbishops score to be superior. 28. METHODS OF CERVICAL RIPENING Unfortunately, women too frequently have an indication for induction butwith an unfavorable cervix. As favorability or Bishop score decreases, there is an increasinglyunsuccessful induction rate. Methods used for cervical ripening include pharmacological preparationsand various forms of mechanical cervical distension. 29. Non pharmacologic means of cervical ripening1. Herbal supplements: evening primrose oil, blue and black cohosh, raspberry leaves.2. Breast stimulation: causes oxytocin release. Advnon invasive, inexpensive, simple Disadv. causes FHR abnormalities.3. Castor oil, hot baths, enemas4. Miscellaneous - acupuncture , sexual intercourse 30. 4. (HYGROSCOPIC DILATORS): Natural osmotic dilators Laminaria japonicum Laminaria digitata Isapgol Synthetic osmotic dilators Lamicel Dilapan They absorb endocervical and local tissue fluids, causing the device to expand within the endocervix and provide mechanical pressure. cause mechanical dilation and release of prostaglandins. Swell up to 4 5 times. Most rapidly in first 4-6 hours but continue to swell up to 24 hours later. 31. ADVANTAGESDISADVANTAGES Skill needed for proper placement in Cheapinternal os. Outpatient placement Delay in obtaining maximum effect. Easy for placement Patient discomfort. No need for fetal monitoring Inability of tents to be molded without Rapid improvement ofcompromising mechanical integrity.cervical status Lack of manufacturer specifications fornatural dilators. Potential for incomplete sterility. ETOgas does not eradicate spores in theinterstices of the sea weed stem 32. 5.Membrane stripping: Release of endogenous PGs. and mechanical dilation. results in < labor inductions < post dated pregnancies > spontaneous onset of labor - inexpensive, safe, efficacious in promoting labor over several days 33. 6.Balloon devices : Single / Double balloon First described in 1967 Safe Cheap ADVANTAGES: The combination of balloon catheter plus oxytocin is recommended as analternative method when prostaglandins (including misoprostol) are notavailable or are contraindicated (previous caesarean) May be useful for outpatient ripening. Can be inserted in presence or absence of membranes. Associated with favorable Bishop scores and no additional side effects. 34. Single Balloon Devices A fluid filled balloon is inserted inside the cervix. A Foley catheter (26 Fr) or specifically designed balloon devices can beused Mechanism of action: The mechanism by which Foley s catheter improves the cervical state is byits mechanical action. It strips the fetal membranes from the lower uterine segment, causingrupture of lysosomes , release of phospholipase A and formation ofprostaglandins. 35. Technique of Balloon Placement1. After sterilization and draping, the catheter is introduced into the endocervix either by direct visualization or blindly by sliding it over fingers through the endocervix into the potential space between the amniotic membrane & the lower uterine segment.2. The balloon is inflated with 30 to 50 mL of normal saline and is retracted so that it rests on the internal os.3. Constant pressure may be applied over the catheter. e.g. a bag filled with 1 L of fluid may be attached to the catheter end / An intermittent pressure may also be exerted on the catheter end 2 -4 times per hour. 36. 4. Catheter is removed at the time of rupture of membranes or may be expelled spontaneously which indicate a cervical dilatation of 3 - 4 Centimeters. 37. PHARMACOLOGICAL TECHNIQUES Prostaglandins PGE2 : Dinoprostone PGE1 : Misoprostol Oxytocin Others Estrogen Relaxin Hyaluronic acid Progesterone receptor antagonist 38. PROSTAGLANDINS The chemical precursor is arachidonic acid PGs are endogenous compounds found in themyometrium, deciduas, and fetal membranes during pregnancy. Cervical production of PGE2, PGI2, PGF increases at term. Modulate fibroblast activity - Increase hyaluronic acid production Acting as chemotactic agents, Inflammatory cells further releasedegradative enzymes, causing cervical ripening. 39. Prostaglandins administration results in dissolution of collagen bundles andan increase in sub mucosal water content of the cervix.These changes in cervical connective tissue at term are similar to those observed in early labor. Unlike oxytocin, response to prostaglandins does not change throughoutgestation. 40. PreparationsPGE2 : Dinoprostone PGE1 : Misoprostol Vaginal gel : Prepidil, CerviprimeTM MisoprostTM Removable tampon : CervidilTM CytotecTM Vaginal pessary : Prostin E2TM 41. Prostaglandin E2: (Dinoprostone)Increase in elastase, glycosaminoglycan, dermatansulfate, and hyaluronic acid levels in the cervix. A relaxation of cervical smooth muscle facilitates dilation.Alter the extracellular ground substanceof the cervixIncrease in intracellular calcium levels,increases the activity of collagenase in ~ contraction of myometrial muscle the cervix. Cervical Ripening 42. PROSTAGLANDIN E2 (DINOPROSTONE): CERVIPRIME GEL -is commonly used for cervical ripening . is available in a 2.5-mL syringe for an intracervical application of 0.5 mg ofdinoprostone. With the woman supine, the tip of a pre-filled syringe is placed intracervically,and the gel is deposited just below the internal cervical os. After application she remains reclined for at least 30 minutes. Doses may berepeated every 6 hours, with a maximum of three doses recommended in 24hours. 43. Prepidil Intracervical placement 44. Dinoprostone should only be administered at hospital. Continuous Uterine activity & FHR monitoring. If optimal response is not achieved by 6 hours, another dose can beadministered. The maximum allowed dose is 3 doses be administered per24 hours. Oxytocin should not be initiated until 6 to12 hours after the last dosebecause of the potential for uterine hyperstimulation with concurrentoxytocin and prostaglandin administration. 45. Cervidil placed in posterior vaginal fornix 46. Vaginal insert containing 10 mg of dinoprostone in a timed-releaseformulation. The vaginal insert administers the medication at 0.3 mg/hand may be left in place for up to 12 hours. ADVANTAGE: the insert may be removed with the onset of activelabor, rupture of membranes, or with the development of uterinehyperstimulation. 47. Vaginal pessary : Prostin E2TM 48. COCHRANE REVIEW Vaginal Prostaglandin E2 versus placebo/no treatment(37 trials, 6511 women) vaginal No Rx / risk 95% PGE2Placebo ratio confidence (RR) interval (CI)risk of the cervix remaining unchanged/5 trials, 467 women 21.6% 40.3%,0.46 0.35 to 0.62unfavourable after12 to 24 hoursreduction in failure to achieve vaginal delivery 2 trials, 384 women 18.1% 98.9%,0.19 0.14 to 0.25within 24 hoursuse of oxytocin augmentation 12 trials, 1321 women 35.1% 43.8% 0.83 0.73 to 0.94Uterine hyperstimulation with FHR changes14 trials, 1259 women 4.4%0.49%,4.14 1.93 to 8.90Hyperstimulation without FHR changes 13 trials, 3636 Women 1.4%0.4%2.48 1.17 to 5.26 49. COCHRANE REVIEWVehicle comparisons PGE2 gel is as efficacious as PGE2 tablets. PGE2 gel does reduce the need for oxytocin augmentation, Gel was associated with less uterine hyperstimulation. Sustained release pessaries in comparison with gel have not been shown to significantly reduce caesarean section rates have not been shown to improve adverse neonatal or maternal outcomes. There is reduction in the use of oxytocin augmentation and the reduction ininstrumental delivery rates. The frequency of vaginal examinations is reduced when using sustainedrelease pessaries. 50. INTRACERVICAL PGE2: although this route of administration iseffective, it offers no advantages when compared to other methods ofadministration, namely the vaginal route. Intracervical prostaglandins are effective compared to placebo, butappear inferior when compared to intravaginal prostaglandins. 51. PGE2 can cause Uterine hyperstimulation, Fetal distress and Cesarean section.Uterine hyperstimulation :- More common with intra vaginal application.- 1-5%, similar to low dose oxytocin