Early ultrasound examination in antenatal care.

Ultrasound examination was done on 442 women early in pregnancy. If there was a discrepancy the date of delivery calculated from ultrasound readings was preferred to that calculated by traditional means. As a result of this policy induction for planned caesarean section was postponed or cancelled in 10.4% of cases. In 9.7% of women the menstrual history was unreliable and the ultrasound measurement was used to estimate the date of delivery. Thus in 21.1% of pregnancies the early ultrasound measurement decided when or whether labour was to be induced. In women induced for postmaturity there was no increase in prolonged labour or need for caesarean section. There were no cases of neonatal respiratory distress and neonatal jaundice was less common than it was when the onset of labour was spontaneous. This evidence suggests that neonatal jaundice is not caused by induction of labour or by the agents used. The low frequency of jaundice in this series is thought to be due to accurate prediction of the expected date of delivery and consequent exclusion of premature babies born to "postmature" women.