[Influence of the environment on perineal tears in physiological delivery]

In the last decades there was a growing interest in new methods of delivery-assistance and in the literature appeared many new studies. This study shows an analysis of all physiological deliveries (581 women) at the Burresi Hospital of Poggibonsi (SI), Italy, in 1993. From 1984, in this hospital an experimental delivery-room (SPN), where new methods of delivery-assistance are tested (151 women in the period of study), has been used in parallel with a conventional delivery-room (SP)(430 women).

The most important difference between the two environments is that in SPN the woman is free to choose her positions during all the phases of delivery. We have evaluated the effect of the different environments on the perineal outcome-intact perineum (41% SPN vs 32% SP), first-degree tears (32% SPN vs 21% SP), second-degree tears (23% SPN vs 21% SP) and mediolateral episiotomy (3% SPN vs 26% SP). Age of the woman, weight of the infant and parity appeared to be most important factors for perineal tears. The SPN reduces significantly the number of perineal tears, when allowing for the other factors.

It was commonly felt that a reduction in the episiotomy-rate increases the number of perineal tears. Our study shows a protective effect for all levels of perineal outcomes associated with the natural delivery-room. However, for primiparous women a higher risk for first-degree tears is documented in the SPN and should be further evaluated. A selection bias cannot be excluded, due to the observational nature of the present investigation.