The effect of maternal obesity on the course of labor.

Aim: To determine whether maternal obesity is associated with dysfunctional labor patterns.

Methods: In a case-control design we compared the graphic labor patterns of a group of 105 very obese subjects [body mass index (BMI) >35 kg/m(2)] with those of 113 lean controls (BMI<26 kg/m(2)). All entered spontaneous labor at term. Cases with birth weights >4 kg, diabetes mellitus, hypertension and prior cesarean delivery were excluded.

Results: The obese group had a significantly higher frequency of arrest of dilatation (17.6 vs. 5.2%; P=0.005).

Conclusions: Maternal obesity is associated with active phase labor dysfunction, specifically arrest of dilatation.