[Epidemiology of prolonged pregnancy: incidence and maternal morbidity]

Objective: To estimate the frequency of prolonged pregnancy and study its associated maternal morbidity.

Methods: Abstracts and articles were searched using Pubmed and Cochrane Library.

Results: Nearly 15% of pregnant women in France are concerned by prolonged pregnancy (≥41(+0) weeks), whereas post-term pregnancy (≥42(+0) SA) only concern 1% of them. The post-term pregnancy frequency is heterogeneous between Europe and United States. It varies between 0.5% and 10% (EL2). In Europe, Scandinavian countries present discrepancies with high proportions of post-term pregnancies between 5 and 7%. These observations identified time variations and variations between countries. They can be explained by two factors: pregnancy datation by ultrasound and the evolution of labor induction practices. Moreover, post-term pregnancy constitute a risk factor of maternal complications as: cesarean section, postpartum haemorrhages, infections and perineum lacerations (EL2). On the contrary, limited conclusions about associations between prolonged pregnancies and labor inductions are due to insufficient data and the lack of high quality studies. Nowadays, we still ignore if labor inductions in the particular context of prolonged pregnancies are associated or not to an increase of maternal morbidities.

Conclusion: Prolonged pregnancy is associated with an excess of maternal morbidity.