Diagnosis, antenatal surveillance and management of prolonged pregnancy: current perspectives

Prolonged pregnancy is defined as a pregnancy that extends beyond 42 weeks of gestation (294 days) from the first day of the last normal menstrual period. An accurate estimation of the 'natural' incidence of prolonged pregnancy would require meticulous early pregnancy dating. The use of ultrasound to establish gestational age reduces the number of pregnancies that are classified as prolonged. Prolonged pregnancy is associated with an increased perinatal mortality and morbidity in pregnancies which appear to be otherwise low risk. Postterm births are easily preventable by intervening to deliver with the use of induction of labor. Thus, this potentially problematic condition deserves further attention and careful consideration. The focus of this article is to review and challenge some current concepts surrounding the diagnosis and management of prolonged pregnancy. We outline how to identify those women with prolonged pregnancy and which is the appropriate moment to start monitoring the fetal wellbeing. Finally we address the question of benefits and hazards of induction of labor strategies.