To estimate if an interventional program causes a decrease in the frequency of anal sphincter ruptures.
A total of 12,369 vaginal deliveries between 2002 and March 2007 were enrolled in the interventional cohort study. Slowing the delivery of the infant’s head and instructing the mother not to push while the head is delivered was the intervention. Data were analyzed in relation to occurrence of anal sphincter tears.
The proportion of parturients with anal sphincter tears decreased significantly during the study period from 4.03% (285 of 7,069) to 1.17% (42 of 3,577) (P<.001). A similar decrease was observed for instrumental deliveries (from 16.26% to 4.90%; P<.001) and noninstrumental deliveries (from 2.70% to 0.72%; P<.001). Although the number of patients with fourth-degree anal sphincter ruptures from 2002 through 2004 was 10, 13, and 11 per year, respectively, there was just one fourth-degree anal sphincter rupture during the whole study period of 18 months (P<.001). The number of episiotomies increased from 13.9% (980 of 7,069) in the years 2002–2004, to 23.1% during the first 9 months of the intervention (416 of 1,776; P<.001), but decreased to 21.1% (381 of 1,801) during the last 9 months of the intervention.
As a result of this intervention the number of anal sphincter ruptures was reduced from 4.03% to 1.17%.
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