Birth and Regulation of head Extension to Guide Manual perineal Assistance (BREGMA) study (a prospective cohort study)

Abstract Background: The exact positioning of the dominant hand at the time of manual perineal protection (MPP) is not clearly specified. The main aim of this work was to identify the place on the perineum where pressure needs to be applied to achieve optimal forward fetal head displacement away from the anal sphincters using the bregma to posterior fourchette distance (BFD) and the perineal body length (PBL). Methods: This was a two-center study. Term cephalic singleton nulliparous women having spontaneous vaginal delivery were considered eligible for recruitment into the study. Once crowning was diagnosed and just prior the initiation of manual perineal protection (MPP) or cutting an episiotomy, the BFD and PBL were measured using a standardized measurement protocol. Results: A total of 100 women (50 women in each center) were recruited into the study. The overall mean BFD was 2.8 ± 0.5 cm. The overall mean PBL was 4.4 ± 0.8 cm. There were no statistically significant differences between the measurements taken in both units regarding BFD or PBL (p = 0.81 and 0.10 respectively). There was a weak correlation between both measurements. Conclusion: Based on our measured parameters, it seems that the most effective point to apply perineal pressure to displace the head away from the anus is approximately 1 – 1.5 cm anterior to the anal margin. This information will form the bases of future biomechanical studies to confirm their validity.