About 10% of pregnancies need to be induced in order to expedite vaginal delivery. This happens when the benefits of delivering the baby outweighs the risks of continuing the pregnancy or awaiting spontaneous labour.
*What are the indications for induction of labour?
-Placenta insufficiency : when the placenta is diseased and no longer capable of supporting the foetus
-Prolonged pregnancy : beyond 41 weeks of gestation
-Intrauterine growth restriction (IUGR) : when the foetus fails to gain weight, or loses weight due to constitutional, maternal or placental disease
– Premature rupture of membranes : when the “bag of water” breaks without any sign of labour after 24 hours (to avoid infection to the baby)
– Intrauterine fetal death – to prevent the risk of toxicity or infection to the mother
– Intrauterine infection (Chorioamnionitis)
– Unexplained antepartum hemorrhage
– Potential or presumed fetal macrosomia : increasing growth beyond 4kg, especially in diabetic mothers
– Medical diseases in the mother : such as severe hypertension, uncontrolled diabetes, cardiac or renal diseases, cancers, etc.
*What are the methods for inducing labour?
Before induction of labour, it is important to assess the cervix to determine its “ripeness”, ie. to predict whether induction is likely to succeed or fail. Predictors of a successful induction includes advanced gestational age (above 37weeks) and multiparity (having delivered by vagina in the past).
The cervix can be ripened through medical and non-medical methods. There is limited evidence to support the efficacy of non-medical methods (eg. Sexual intercourse, nipple stimulation, herbal mixtures, dates, castor oil, etc.)
The medical methods of ripening are :
1. Mechanical methods – this includes using the finger to “stretch and sweep” the cervix and/or insertion of a catheter into the cervical canal.
2. Pharmacological methods – use of chemical agents (prostaglandins and oxytocin)
Certain parameters are used by the midwives/physicians to “score” the ripeness of the cervix. After satisfactory ripening, induction of labour proper begins. This can be done in one of two ways –
~Artificial rupture of membranes – Deliberately breaking the “bag of water”, which stimulates the process of active labour through the release of prostaglandins.
~Induction/Augmentation of labour using oxytocin infusion – Oxytocin is released normally by the brain at the time of labour. This process can be augmented by infusion of controlled amount of oxytocin (Syntocinon®) through dedicated intravenous infusion pumps.
*Note that induction of labour MUST be done in a hospital where adequate feto-maternal monitoring and standard obstetric care are available. This will ensure that any complication in the course of induction can be identified promptly and treated appropriately.
It is also better to have standby facilities for Caeserean section in case of complications during, or failure of induction of labour.
Wishing all expectant mothers safe delivery!