Induction Of Labour PROF. M.C. BANSAL MBBS.,MS.MICOG.,FICOG
Induction Of LabourDefinition Induction of labour after 28 wks of gestation i.e. after period of viability but before spontaneous onset of labour with aim of vaginal delivery.
Induction Of Labour The list of indication has lately been expanded to cover a large number of maternal and fetal conditions with the objective of reducing Maternal Mortality & Morbidity ; as well as salvaging LIVE babies . The major risk is Iatrogenic Prematurity . The Obstetrician is solely responsible for this and hence it is mandatory to establish fetal lung maturity (presence of surfactant factor) OR be certain of fetal gestational age by serial ultrasonography first / second / third trimester , all inclusive .
Indications1.POST DATED PREGNANCY Beyond 40 wks of gestation, placental insufficiency Chronic Fetal Hypoxia – Fetal Death. Fetal asphyxia worsens with each week of advancing leading to a severely compromised fetus and IUFD. Reported fetal loss in Post dated pregnancy 0.7% at 37 weeks 5.8% at 43 weeks ( 8-fold increase).
Indications1.POST DATED PREGNANCY (contd) Timing of induction –controversial-- some prefer to wait spontaneous onset of labor till 42 week, many others believe there is no gain in waiting beyond 40 weeks. CS rate rises sharply after 40 weeks. Cost and stress of fetal monitoring while waiting for spontaneous labor to start . Need for emergency intervention --are the risks of wait & watch policy. Good success rate achieved with Induction with Prostaglandins at 40 weeks Prompts many Obstetrician to intervene if fetal maturity is reached..
Indications2. HYPERTENSIVE DISORDER Hypertensive disorder of any origin can cause placental insufficiency, IUGR fetal anoxia depending upon severity and duration of hypertension. Cerebra-vascular accidents ,eclampsia and abruptio placenta can endanger maternal life. Induction is planned at 37 weeks as fetal maturity is gained. But in state of worsening ---impending eclapmsia, IUGR and placental abruption may require early induction ---Corticoid therapy between 30-34 weeks will reduce the risk of RDS in Newborn.
Indications3.ECLAMPSIA Once eclampsia supervenes , maternal and fetal mortality rises. Once the measures for controlling fits are done and patient is stabilized, induction of labour / Caesarean Delivery should be undertaken.
Indications4.DIABETES A sudden IUFD is not uncommon in last 6 weeks of pregnancy complicated by long standing severe Diabetes. Monitoring Biophysical profile at twice week interval and fetal lung maturity will determine the time and method of termination of pregnancy. Strict control of maternal blood sugar level, avoiding maternal Ketoacidosis and fetal prematurity and sudden IUFD must be the aim to be gained.
Indications5.Rh INCOMPATIBILITY A pregnancy complicated by Rh iso immunization exposes the fetus to anaemia, jaundice and kernicterus . Amniocentasis, cordiocentasis and USG screening done repeatedly can help to determine severity of fetal affliction and time of induction. Post maturity not allowed. Pregnancy should be terminated as soon as lung maturity is gained / fetal condition in utero is in state of impending danger.
Indications.6.ANTEPARTUM HEMORRHAGE In placenta praevia nothing is gained by going beyond 37 weeks as bleeding may start at any moment . Severe bleeding and concealed hemorrhage in abruptio placenta need immediate termination of pregnancy.
Indications.7.INTRA UTERINE GROWTH RETARDATION IUGR due to any cause results in chronic fetal asphyxia. Further growth is impaired. Fetus is worse off in utero than out side. The optimal time for induction is determined by bio physical profile.
Indications8.PREVIOUS INTRA UTERINE FETAL DEATH (IUFD) It is desirable to terminate the pregnancy one week before the time when IUFD occurred in last confinement.
Indications9.PREMATURE RUPTURE OF MEMBRANES (PROM) PROM leads to infection ,cord compression, Oligohydramnios and fetal pneumonia. If pregnancy is beyond 37 weeks and PROM has lasted more than 12 hrs without labour pains –Induction of labour is indicated.
Indications10.DEAD FETUS(IUFD Present Pregnancy). To avoid infection and DIC , Pregnancy with dead fetus should be terminated by medical induction as early as possible . DIC earliest documented after 5 days
Indications.11.MALFORMED FETUS. Gross malformation of fetus incompatible with life necessitates termination. The routine practice of USG in mid trimester eliminates the delayed detection of gross fetal malformation in late pregnancy .
Indications12.UNSTABLE LIE Stabilizing induction is sometime recommended in a multipara. Stabilizing induction may effect vaginal delivery and avoid a caesarean section.
Indications13.SOCIAL INDUCTION• Also known as elective induction for convenience of family and obstetrician must be discouraged .Induction by any method is not 100% successful.• Failed induction may necessitate unneccessary LSCS.
Indications For Caesarean Section Medical /Surgical induction is contraindicated, but early termination of pregnancy is must to save guard the life of mother and fetus. When CS is selected on obstetrical grounds such as Contracted Pelvis , Abnormal Fetal Presentation / Position , Previous scar of CS , Hysterotomy, Myomectomy etc.
Pre-induction Evaluation1.Indication-One must be certain that induction of labour is warranted in a particular woman. The balance between Risks and advantages of induction and continuation of pregnancy must go in favor of induction.2.Time of induction– Iatrogenic prematurity should be avoided. In maternal indications fetal maturity is less important e.g. Status eclampticus.If premature induction is planned , Corticosteroid therapy will reduce the risk of Fetal RDS / Hyaline Membrane Disease.
Pre-Induction Evaluation 3.Bishop Score Score O 1 2 3CervicalDilatation <1cm 1-2cm 2-3cm >4cmEffacement 0-30% 40-50% 60-80% >80%Cervical length >2cm 2-1 cm 1-0.5 cm <0.5 cmConsistency Firm Medium Soft --Station -3 -2 -1 , 0 +1,+2 >3 cm >2cm < 2 cm 1+,2 + cm above above I.S. above I .S. below I.S. Ischial spineCervical Mid AnteriorPosition Position Posterior
Pre-induction Evaluation 4.Pelvic Assessment Pelvic assessment should be done to confirm whether vaginal delivery is possible or not. The success of induction depends on parity of woman, gestational age, Bishop Score. Bishop score of >9 is very favorable and nearly 100% success in induction is expected. 6-9 Bishop Score--70-80% success , Bishop Score<6 is associated with > 20% failure rates.
Methods of Induction of Labour1.Mechanical Laminaria Tent Nipple Stimulation Sweeping membranes Extra Amniotic insertion catheter/balloon2.Surgical ARM3.Medical Prostaglandin (Cerviprime/Dinoprostone) Relaxin gel, Prostaglandin Tablets (Primiprost) , Misoprostol Tablets , Oxytocin, Mifepristone , Oestrogen pessary .4.Combined Surgical and Medical
1. Mechanical Methods Laminoria tent--A stem of sea weed imbibes water and swells up ,slowly dilates Cx.Local prostagandins are also released. Lamicel,Isogel tent are also used. Disadvantages---Slow dilataion,infection,accidental ARM,not recomonded in IUFD cases. Nipple Stimulation--It releases pitocin from Posterior pituitary and initiate uterine action Failure rate is very high Sweeping of membranes--PG released .Cervical stretching --Ferguson reflex. Extra Amniotic insertion of catheter/balloon--Mechanical stretching of Cx and separation of membranes release PG. catheter is removed after12 hrs and Syntocinon drip is started. Displacement of presenting part , ARM Infection may
2.Surgical methods ARM--to be done in morning hrs when pt is empty stomach--risk of cord prolapse--immediate LSCS may be undertaken. Precautions-- Timing-- when Cx is dilated >3cm. Visualise colour of amiotic fluid for meconium staining. Application of scalp electrodes for fetal heart monitoring. Syntocinon drip started after 12 hrs/earlier . Watch for any bleeding in cases of APH , bleeding increases or decreases.
2.Surgical methods ARM Risks of ARM 1.Cord prolapse when presenting part is not engaged. 2.Sepsis if time interval is prolonged / multiple PV examinations are done. 3.Failure of induction , when Bishops Score is < 6. Contraindications of ARM Abnormal Fetal Presentation : Transverse Lie , Breech , Brow , ROP , Face , Multiple pregnancy . Unengaged head Dead Fetus--Sepsis.
3.Medical Methods Locally acting- 1. Oestradiol 150mg Vaginal pessary OD/BD –PV insertion help in ripening the cervix in 90% cases.It releases PG and proteolysis leukocyte Induce ripening.Collegen content is reduced & Cx Is softened. 2. Relaxin 2mg gel exerts similar action. 3. Anti Progesteron (RU 486)- Mefepristone---enhances PG action.200 mg daily for2days prior to formal induction is effective in softening and effacement of Cx. 4.PGE2 & PGF2 a -----PGE2 acts mainly on Cx and cause cervical ripening. PGF2a Initiates uterine contractions Not recommended.
3.Medical MethodsPGE2 - 500ug viscous gel or 50ug in 0.5ml injection repeated every ½ hrly (Maximum 3 ml ) through extra amniotic transcervical foley’ catheter. It starts cervical softening and uterine action.PGE2 is 5-10 times more potent. This method bears disadvantages of mechanical methods and fetal distress. PGE2 gel ½ ml (0.5) ml (cerviprime/dinoprost) is instilled in cervical canal. Cervical ripening occurs in 40% cases with in 4-6 hrs.15% may not have any response. PGE2 tabs-3mg and 1mg- gel available . PV gel is rapidly absorbed and more effective than tabs. Dose may be repeated 3hrly according to status of FHS and uterine action. Hypertonicity is reported 7.3% and 0.5% with tablets and gel respectively.
3.Medical Methods Misoprostol(PGE1) -- It is stable at room temperature. Its half life is 3 yrs ,GI disturbances and fever are its disadvantages. Misoprostol 25ug 3 doses at 3hr interval is effective . Higher dose 100ug 4hrly orally /400ug 3hrly given sublingually but GI symptoms are sometime troublesome. Monitoring for fetal distress ,hyper tonicity is must.Glycerol trinitrate induces painless induction.Nitric oxide skin patch (50mg) with a surface area of 20 cm acts fast in 24 hrs.
3.Medical Methods Systemic drugs 1.Oral Prostaglandin 2.Syntocinon Drip 1. Oral Prostaglandin - A 0.5 mg tablet of primiprost/Prostin is taken as 1st dose . Dose is increased as ½ tablet every hrly until 3 contractions are there in each 10 minutes /maximum 3 tablets are administered. Contraindications for PGS -- Bronchial Asthma , Cardiac disease PGE2 causes hypotension , PGF2a causes hypertension & tachycardia , Glaucoma , Epilepsy , Renal disorders , Fetal distress , Previous LSCS/SCAR. Side Effects-- Nausea, vomitting, diarrhoea, Burning in vagina, Cervical tear, Uterine Rupture in1% cases mostly multiparas . Fetal distress , Hyperstimulation Syndrome , Amniotic Fluid Embolism , Failure 10-20 % require LSCS.
3.Medical methods 2. Syntocinon Drip Synthetic version of Oxytocin a hormone secreted by posterior pituitary gland. It is a Neuropeptide synthetized in supraoptic and paraventricular nucleus of the Hypothalamus and released into post pituitary veinous plexus. Its ½ life is 3-4 minutes and effect lasts for 15-20 minutes. Syntocinon –orally-desrtoyed in stomach, irregular and slow absorption when given buccal/sublingual route . If given IM rapidly destroyed by Oxytocinase enzyme.
3.Medical methods 2. Syntocinon Drip Syntocinon -- How to start? By titration method - one unit in 500ml 5% GDW/saline10-15 drops/minute drip started. Uterine action and FHS monitored ,dose is Increased gradually as per uterine action & FH rate, till 3 contractions in 10 minutes start . Syntocinon drip is stopped if there are signs of fetal distress. It is necessary to maintain the drip after delivery for at least 2-3 hrs to avoid delayed PPH. Oxytocin infusion pump--Can regulate the dose of drug and control the uterine action effectively as well as limit I V Fluids.
3.Medical methods 2.SyntocinonIndications1. Induction, Augmentation, acceleration of labur.2. Control of atomic PPH in higher dose (20-40units in running drip).3.In abortion , MTP, Vesicular Mole - evacuation.4. Prophylactic use in 3rd stage of labour. 5.Letting down reflex for milk secretion, breast engorgement. 6.Secondary uterine inertia in prolong labour case if there is no fetal distress/ inco-ordinated uterine action .
3.Medical methods Syntocinon Complications1. Hypertonic uetrine action---rupture uterus.2.Fetal distress and fetal death.3.Delyed PPH if drip is withdrawn soon after delivery.4.Maternal Hypotension if given in volous form. . Waterintoxication,hypernatraemia.,convulsiovn and coma.6.Amniotic fluid embolism.7.Hyperbilrubinaemia in newborn..
4.Combined Methods Combined method ( medical & surgical) is often required in induction of labour , it yields 80% of success rate .
Special Conditions1.Dead fetal--Cervical ripening by PGs, augmentation by syntocinon and ARM Under antibiotic .Extra amniotic instilation of emicradil100-200ml.2.Previous Caesarean Section--The choice depends upon Bishops score , integrity of scar.3.Twin Pregnancy--only indicated when1st fetus is LOA.4.Breech Presentation--No ARM. Cervical ripening needs careful monitoring. LSCS is considered safer than induction.5.PROM--Longer the interval between PROM and delivery, greater is risk of infection and fetal distress.PGE2 vaginal Tablet or syntocinon drip is indicated if uterine contraction do not start within 12hrs of PROM.
Choice of Method It depends upon parity,station of presentng part,State of membranes , Bishop’s score, Period of gestation. Low parity , low Bishops score predisposes to prolonged labour and poor neonatal outcome -- higher incidence of LSCS. PGS have improved the success rate, hence used more to ripen Cx improve Bishops score and initiate uterine action. Syntocinon drip is used when PGS fail or added to augment.
Failure of Induction It is defined when Cx failed to dilate up to 3-4 cm in 24 hrs of induction. What to do now ? - Option to wait-- if No PROM and postponement is not harmful for fetus as well as mother. - Review the case and if there is urgency, Caesarean delivery is performed.