[Maternal effects of prolonged expulsive efforts]

Some studies found an association between duration of expulsive efforts (DEE) and risk of postpartum haemorrhage (PPH). But none demonstrated an association between DEE and severe perineal lacerations. Our aim was to evaluate the impact of prolonged expulsive efforts (EE) beyond 45min on the risk of maternal complication, especially risk of severe perineal laceration.

We performed a retrospective study comparing 2 groups, 1: women with an instrumental vaginal delivery performed before 45min for non-fetal progression without FHR abnormalities (VBI for NP<45min) and 2: women with a DEE longer than 45min (DEE≥45min). We compared maternal issues (3rd and 4th degrees perineal lacerations and PPH), using uni- and multivariate analysis.

We compared 85 women in group VBI for NP<45min with 124 women in group EE≥45min. In the group EE≥45min, 39% of women had an instrumental vaginal delivery versus 100% in the group VBI for NP<45min (P<0.001). The rate of severe perineal lacerations was significantly higher in the group VBI for NP<45min (8.2% versus 1.7%, P=0.027) and its risk remained significant after adjustment (adjusted OR=6.5 [1.1-40.1]). The rate of PPH was higher in the group EE≥45min (12.9% versus 3.5%, P=0.016), however this association was not significant after adjustment (adjusted OR=3.4 [0.9-12.4]). There was no difference about neonatal issues between the two studied groups.

In comparison with a limitation of EE, to prolong EE beyond 45min allows a spontaneous vaginal delivery for more than half of women, if FHR is normal. Such strategy should also decrease the risk of severe perineal laceration.