Perineal outcomes on the left lateral versus vertical semi-sitting birth positions: a randomized study

Objective: To evaluate the perineal outcomes in unconventional birth positions. Methods: A randomized clinical study. Conducted in a birth centre in the city of Ttapecerica da Serra, Brazil. A sample of 158 nulliparas, divided randomly into the left lateral position (81 - experimental) and upright half-sitting (77 - control). Results: Experimental group showed less vulvar edema, 13.6% vs. 29.9%, OR 2.71 (95% IC 1.22 -6.02), episiotomy, 16.0% vs. 35.1 OR 2,46 (95% IC 1, 27 - 4.74), and more labial lacerations 37,0% vs. 19,5% OR 2,43 (95% IC 1,18 - 5,51). The women who adopted the upright half-sitting position had a lower risk of first-degree laceration (37,7% versus 56,8%). However, they had a higher risk of second-degree laceration and frequency of episiotomy OR 2,11 (95% IC 1,02 - 4,35). The presence of vulvar edema increased the risk of spontaneous trauma and episiotomy OR 3,99 (95% IC 1,80 - 8,85). Conclusions: Our data confirmed the hypothesis that the left lateral position offers less risk of serious perineal traumas.