Prolonged pregnancy.

The perceived risks to the fetus of the postmature syndrome have led to the obstetrician's dilemma of whether to await spontaneous parturition or to artificially bring forward the onset of labor to an arbitrarily defined gestation. A prolonged or post-term pregnancy relates to a gestation of greater than 42 weeks and should not be regarded as synonymous with postmaturity. The latter describes a clinical syndrome thought to be a consequence of failing placental function. It is the difficulty in identifying the 'at risk' fetus which has led to routine induction policies. But is such a policy justified in terms of fetal outcome, and if so, is the mother put at increased risk? This review puts into perspective the most recent publications and points out areas requiring further study.