Post-Term Pregnancy

Post-term pregnancy is one that progresses to 42 weeks' gestation. A key in making the proper diagnosis of post-term pregnancy is accurate pregnancy dating, best done with confirmational first-trimester ultrasound. The epidemiology is the opposite to preterm birth, with higher rates in obese women and those of white race/ethnicity. Such prolonged pregnancy is also seen more commonly with fetal complications such as anencephaly and placental sulphatase deficiency, pointing towards a fetal contribution to the initiation of labour. Complications of post-term pregnancy include higher rates of stillbirth, Caesarean delivery, meconium-stained amniotic fluid, neonatal acidaemia and neonatal death. One advantage of post-term pregnancy is that it is easily preventable with induction of labour. However, the timing of such induction during the term period is costly and understudied.