Interventional program to reduce both the incidence of anal sphincter tears and rate of Caesarean sections

To estimate the ability of an intensive interventional program to decrease the number of obstetric anal sphincter injuries (OASIS), while simultaneously decreasing the rate of Caesarean sections (CS).

The intervention, which aimed at decreasing the number of OASIS, started with a compulsory tutorial for all the midwives and physicians. At the same time, the clinic initiated a program to decrease the number of CS. We compared the outcomes before and after the intervention by calculating the risk ratios with 95% confidence intervals. The changes in selected outcomes were also tested using the test of relative proportions. The follow-up was extended for 1 year after the intervention.

The number of deliveries by CS decreased significantly, as did the number of OASIS in all the subgroups, except for the multi-parous women. The rate of OASIS for instrumental deliveries (mostly by vacuum) decreased significantly (p < 0.003), as compared to pre-interventional period. The number of Grade 4 tears decreased significantly: from 0.4 ruptures per 100 deliveries before the start of the intervention to 0.1 ruptures after the start of the intervention (RR 0.37, 95% CI 0.14-0.98, p = 0.037). However, the OASIS and Grade 4 sphincter injuries increased with forceps delivery. The CS rate decreased from 17.7 to 15.0 per 100 deliveries (RR 0.85, 95% CI 0.78-0.93). The post-interventional follow-up period revealed a further decrease in the frequency of OASIS (to 1.28%, p < 0.001) and a stable CS rate (14.2%).

The intervention significantly decreases the frequency of OASIS, in line with the results obtained for earlier interventions. At the same time, a decrease in CS rate was obtained.