Induction of human labor at term: uterine activity, inducibility, duration and neonatal jaundice

A total of 821 patients, 39-40 weeks pregnant, was obstetrically normal at admission. In 212 of them intra-uterine pressure (IUP) was monitored before and during inducing labor by oxytocin, in 212 patients delivery was also induced by oxytocin but not monitored, in 197 by combining oxytocin and amniotomy, and 200 had spontaneous delivery. Inducibility could be predicted by uterine baseline activity and a 50 mu i.v. shot of oxytocin, together with determination of cervical status and placental location. The duration of labour induction was affected by parity, placental location and cervical status, but was predicted only to a minor degree by baseline activity and uterine oxytocin sensitivity. Amniotomy did not affect caesarean, section rate. The newborn child benefited from IUP monitoring: fewer transfers to pediatrics were necessary, there was less neonatal jaundice and fewer blood exchanges. It is assumed that if labor is not monitored through IUP, oxytocin may cause neonatal hyperbilirubinaemia through episodes of increased uterine resting pressure.