[Prolonged pregnancy. Review of the literature]

There have been various estimations of the frequency of postdate pregnancies. On the average, 10% of all pregnancies exceed 42 weeks amenorrhoea with a range from 4 to 14% according to the authors. Rates vary with use of ultrasound examinations early, avoiding false dating and induced labour. A pregnancy becomes a pregnancy at risk at the end of the 41st week of amenorrhoea. Fetal maturity may be affected by a disease process or due to individual or ethnic variations. The potential danger of prolonged pregnancy is inhalation of meconium prepartum. Expulsion of meconium is both a frequent consequence of fetal distress and the result of increased intestinal reactivity. There does not appear to be agreement on the degree of risk of sudden death at the end of pregnancy, although the risk does appear to exist. Surveillance should include recording fetal heart rate under basal conditions and an assessment of the amniotic fluid volume with ultrasounds. The Doppler technique is currently under study. When the status of the cervix is favourable, labour may be induced by rupturing the membranes of with a perfusion of Syntocinon. When the status of the cervix is unfavourable, prostaglandin E2 is applied intravaginally or intracervically with a gel. Therapeutic trial published to date do not demonstrate any advantage over cesarean section or fetal morbidity. The safety of the procedure has not been proven. Randomized trials comparing systematic induction of labour with a wait-and-see attitude have not given a definitive answer. Only two trial have shown a significant advantage of systematic induction of labour. The others have shown that the rate of cesarean section and neonatal morbidity are comparable in the two groups.