Induction of Labour

INDUCTION OF LABOUR

At the end of this chapter the students will be able to:

·        Identify indications of induction of labour

·        Mention standard protocol of induction

·        Define Augumentation

·        List indicators of failure of trial of labour

Definition: Induction is the initiation of labour by artificial means Labour should be induced for medical or obstetrical reasons.

Type

i.                     Medical - using drugs alone Syntocinon & prostaglandin E₂

ii.                     Surgical-aminiotomy or membranes sweep

iii.                     Combined - medical & surgical.

Indications for Induction

·        Prolonged pregnancy (post term pregnancy)

·        Pre eclampsia, eclampsia and diabetes

·        Evidence of diminished fetal well being or growth

·        Elderly primigravida

·        Poor obstetric history

·        Spontaneous / premature rupture of membrane

·        Previous large baby

·        Rhesus iso - immunization

·        Unstable lie

·        Genital herpes

·        Previous precipitate labour

·        Placenta abruptio

·        intrauterine death 

Contraindication

·        Unreliable EDD

·        Malpresentation

·        Cephalopevic disproportion

·        Fetal distress

·        Psychological distress

Factors which affect induction of labour

A .Fetal maturity and viability

B .Favorability of cervix

Favorability of cervix is assessed by a score system called ‘’Bishop”score.It has to be done before induction. The score is scored out of 20.Score of greater or equal to 7is favorable. There are four factors considered, each accounts a score of 0-3.

 Table 6 .Bishops Score System 

Preparations

·                 Admit 24 hrs before hand

·                 Sedate at night no breakfast

·                 Vulval preparation

·                 Psychological preparations 

Methods

Medical method

·        Prostaglandin E₂

-                  Vaginal prostaglandin

-                  Endocervical prostaglandin

-                  Extra amniotic prostaglandin

-                  Oral

·        Intravenous oxytocin / syntocinon/ infusion

Aim - To achieve 3 contractions per 10 minutes lasting 40-60

Table 7. Procedure of induction for multipara and primigravida 

In induction

·        delivery  interval  doesn’t  exceed  18  hours;  if  not ceaserean section is indicated.

·        If no labour starts in 6 hours- consult

·        If contractions are very strong and tetanic stop drip, sedate and consider ceaserean section.

Observation of mother and fetus

·        The fetal heart rate

·        Uterine contractions

·        Fluid balance chart

·        Urine test for ketoses

·        Progress in labour

·        Abdominal & cervical examination every 2-4 hours

After delivery continue oxytocin drops for one hour to prevent PPH.

Complications of medical induction

·        Over stimulation of the uterus causing fetal distress, precipitate labour or uterine rupture.

Amniotomy (Surgical induction)

Amniotomy is artificial rupturing of amniotic bag or membranes. Rupturing these if they do not rupture spontaneously allows the fetal head to contact the cervix more directly and may increase the efficiency of contractions. The membranes are torn and amniotic fluid is allowed to escape.

Complications:

·        Cord prolapse

·        Placental separation

·        Intrauterine infection if labour is not completed with is 24 hours of rupture of membrane and prophylactic antibiotic is not given.

Contraindications:

·        High head

·        Unripe cervix

·        Malpresertaions

·        Intrauterine death