Objective: To evaluate the influence of mediolateral episiotomy on the perineal state after spontaneous, singleton vaginal deliveries with fetus in the occiput anterior position.
Design: The study was a population based, observational study. Two approaches were used in the analyses. Initially, we considered the parturients as quasi-randomised to one of three equally sized groups of midwives with different attitudes towards episiotomy. Secondly, we studied the effect of episiotomy on the state of the anal sphincter, controlling for birthweight, parity, and duration of second stage of labour.
Subjects: 2188 pregnant women delivering consecutively.
Main outcome measures: Perineal lacerations and tear of the anal sphincter.
Results: Women allocated to the group of midwives with the lowest rate of episiotomy were more likely to have intact perineum after delivery (OR = 1.8 (1.4-2.2)), had a slight tendency towards more perineal lacerations (OR = 1.3 (1.0-1.5)), but no increase risk of having tear of the anal sphincter, compared with the women allocated to the two groups of midwives with higher frequencies of episiotomy. The second approach showed that episiotomy was related to an increased risk of tear of the anal sphincter (OR = 2.3 (1.2-4.6)). However, this relation was not found among the group of parturients delivered by the midwives with the lowest rate of episiotomy (22%).
Conclusions: Our results encourage a conservative approach to the use of mediolateral episiotomy, and in the light of previous findings, it seems reasonable to suggest that episiotomy should ideally be used in about one in five spontaneous vaginal deliveries.