Induction of Labour
It is artificial initiation of labour after viability of the foetus i.e. after 28 weeks.
Modified Bishop Score
This score is predicting for the succession of induction of labour. The total score is in the range of 0-13, a score of 9 or more is favourable for successful induction.
Methods of Induction
It is suitable to begin with it the trials for induction of labour and consists of:
In most of the cases with favourable Bishop score labour is commenced within 24 hours.
They induce ripening of the cervix and uterine contractions.
Prostaglandins can be administered via many routes (see ecbolics) but the commonest are:
Extra-amniotic normal saline
A Foley’s catheter is passed extra-amniotically through the cervix and inflated with 10 ml of distilled water to be self retained . A drip of normal saline is connected to it to pass extra-amniotic in a rate of 1 ml/minute.
Artificial rupture of membranes (amniotomy)
Mode of action:
Amniotomy alone results in delivery within 24 hours in about two-thirds of cases.
It is now a common practice to administer oxytocics at the time of or soon after, amniotomy to shorten the latent phase. The majority of deliveries then occur within 12 hours.
Mode of action: It depolarises cell membrane potential and alter permeability to sodium. The maximal sensitivity to oxytocin is achieved by 34-36 weeks’ gestation.
Method of administration: The initial rate of administration is 6 m units/ minute, increased by 6 m units/ minute every 15 minutes up to a maximum of 36 m units/minute or until 3 contractions/ 10 minutes are achieved.
Practically, this is done by putting 5 units of syntocinone in 500 ml of 5% glucose and start the IV drip by 10 drops/min. to be increased by 10 drops/ min. every 15 min. up to a maximum of 60 drops/min.
The oxytocin drip is continued through out the second, third and fourth stage of labour to guard against postpartum haemorrhage.
Hazards of oxytocin: (see ecbolics).
Failed induction of labour → caesarean section.
Edited by Aldo Campana,