Induction of Labor PDF

Induction of labour Dr Alaa yousif mahmood obstetric and gynecology department MRCOG (LONDON)/DOG/M.B.ch.B  Definition SOE Induction of labour(IOL) is the planned initiation of labour prior to its spontaneous onset. PRIOR TO ITS...

Induction of labour Dr Alaa yousif mahmood obstetric and gynecology department MRCOG (LONDON)/DOG/M.B.ch.B  Definition SOE Induction of labour(IOL) is the planned initiation of labour prior to its spontaneous onset. PRIOR TO ITS spontaneous onset Approximately 20– 25% of deliveries in the UK occur following IOL. Broadly speaking, IOL is performed when the risks to the fetus and/or the mother of the pregnancy continuing outweigh those of bringing the pregnancy to an end. It should only be performed if there is a reasonable chance of success and if the risks of the process to the mother and/or fetus are acceptable. If either of these is not the case, the woman should be advised to await spontaneous onset of labour or a planned caesarean section should be performed  Indications for induction of labour I ØProlonged pregnancy (usually offered after 41 completed weeks). ØPROM. ØPre-eclampsia and other maternal hypertensive disorders. - ØFGR. ( I U 6 R ) - IUFD o r H× of i t PROM HEE ØDiabetes mellitus. ØFetal macrosomia. ØDeteriorating maternal illness. ØUnexplained antepartum haemorrhage. DM Ø Twin pregnancy continuing beyond 38 weeks. PRE Echnn Ø Intrahepatic cholestasis of pregnancy. maolin ØMaternal isoimmunization against red cell antigens. ‘ unexplained ØSocial’ reasons of ( e. m o t h e r i s s t u d e n t and h a s e x a m s after APH 2 weeks)  Indication for IOL Prelabour rupture of membranes (PROM) The longer the delay between membrane rupture and delivery of the baby, the greater the risk of ascending infection (chorioamnionitis) and neonatal and maternal infectious morbidity. At term (beyond 37 weeks), good-quality evidence supports IOL approximately 24 hours following membrane rupture. It reduces rates of chorioamnionitis, endometritis and admissions to the neonatal unit. The evidence is less clear at present when PROM occurs preterm (PPROM). Before 34 weeks, some other additional indication is needed to justify IOL if the membranes rupture (e.g. suspected maternal infection, fetal compromise, growth restriction). Between 34 and 37 weeks, in an otherwise straightforward pregnancy, the risks and benefits of IOL need to be assessed on an individual basis.  Indication for IOL 720ns The most common reason for IOL is prolonged pregnancy (previously described as ‘post-term’ or ‘postdates’). There is evidence that pregnancies extending beyond 42 weeks’ gestation are associated with a higher risk of 42h stillbirth stillbirth, fetal compromise in labour, meconium aspiration and mechanical problems at delivery. Because of this, women are usually recommended IOL between 41 and 42 weeks’ gestation. conium Aspiration Me Induction for prolonged pregnancy does not increase the rate of caesarean section. In fact, it decreases the need for C/S Tree  Contraindications to IOL There are a number of absolute contraindications to IOL including : placenta praevia 70 severe fetal compromise. EE.e Deteriorating maternal condition with major antepartum haemorrhage, pre-eclampsia or cardiac disease may favour caesarean delivery. Breech presentation is a relative contraindication to IOL, and women with a previous history of caesarean birth need to be informed of the greater risk of uterine rupture. Preterm gestation is not an absolute contraindication, pimdn  Bishop score The Bishop score As the time of spontaneous labour approaches, the cervix becomes softer, shortens, moves forward, effaces and starts to dilate. This reflects the natural preparation for labour. Bishop produced a scoring system to quantify how far this process had progressed prior to the IOL. High scores (a ‘favourable’ cervix) are7078 associated with an easier, shorter induction process that is less likely to fail. Low scores (an ‘unfavourable’ cervix) point to a longer IOLthat is more likely to fail and result in caesarean section.  Methods of induction OF Labour - D i n oP r o s to n e CP6 Ez) Membrane sweep (offer weekly from 40 weeks). I Prostaglandin gel, tablet or pessary to ripen cervix and initiate contractions. ARM (cervix must be favourable). artificial rupture of membranes Oxytocin infusion (membranes ruptured first, spontaneous or artificial). Mifepristone and misopostol (for intrauterine fetal death). Extra-amniotic saline infusion Mm  Membrane sweeping Membrane sweeping’ describes the insertion of a gloved finger through the cervix and its rotation around the inner rim of the cervix. This safe technique strips off the chorionic membrane from the underlying decidua and releases natural prostagl andins. It can be uncomfortable for the woman, and is only possible if the cervix is beginning to dilate and efface. It can be performed more than once and evidence shows that it reduces the need for induction. It is usually only performed at term, and placenta praevia must be excluded before it is offered. It should be considered an adjunct to the normal processes of induction.  Oxytocin and prostaglandin Oxytocin has a short half-life and is given intravenously as a dilute solution. The response to oxytocin is highly variable and a strict protocol exists for its use. The starting infusion rate is low and defined increments follow every 30 minutes until 3–5 contractions are achieved in every 10 minutes dose depends o n G A , Parity & p r e v i o u s C's Synthetic Prostaglandin. → + dose w i t h P G A , In parity & Previous C 1 S Various routes and preparations have been used, but the most common formulation in current use is prostaglandin E2 (PGE2), inserted vaginally into the posterior fornix as a tablet or gel. Two doses are often required, given at least 6 hours apart. A controlled-release pessary is also available and this is left in place for up to 24 hours. Mifepristone (an antiprogesterone) and misoprostol (another prostaglandin) can be used to induce labour, but complication rates seem higher and this drug combination is currently used in the UK only to induce labour following intrauterine fetal death.  Complications of induction of labour It is generally agreed that a woman is likely to experience more pain with an induced labour and the use of epidural analgesia is more common. The rates of instrumental delivery are higher where epidural analgesia is used, but two recent systematic reviews show no evidence of a higher rate of caesarean section. Long labours augmented with oxytocin predispose to PPH secondary to uterine atony. Fetal compromise may occur during induced labours and this, in part at least, is due to uterine hyperstimulation as a side-effect of use of prostaglandins and oxytocin  Complications of induction of labour A contraction frequency of >5 per 10 minutes should be treated by stopping the oxytocin and if necessary administration of a tocolytic drug, most commonly a subcutaneous injection of the β2-agonist terbutaline. Uterine hyperstimulation may precipitate a fetal bradycardia and the need for emergency caesarean section if the FHR fails to resolve promptly. If ARM is performed while the fetal head is high, then cord prolapse may occur, again precipitating the need for emergency caesarean section. Women with a previous caesarean section scar are at greater risk of uterine rupture if they are induced. The risk of scar rupture increases from one in 200 in a spontaneous labour to as high as 1 in 70 if IOLis performed using prostaglandins.  Failure of induction of labour IOL may fail and this is said to have occurred if an ARM is still impossible after the maximum number of doses of prostaglandin have been given or if the cervix remains uneffaced and less than 3 cm dilated after an ARM has been performed and oxytocin has been running for 6–8 hours with regular contractions. e When an induction fails, the options include a rest period followed by attempting induction again at some point in the future, or performing a caesarean section. Delaying delivery further is only acceptable if there is no major threat to fetal or maternal condition. This may be the case with a failed social induction, for example. Failed induction in the setting of pre-eclampsia or FGR will usually necessitate a caesarean delivery.