Third degree tears and episiotomy

Objective: To investigate the relation of episiotomy to third degree perineal tears, and to detect the rate, indications and risk factors of both episiotomy and third degree perineal tears. Methods: Between 1994 and 1999, 17,559 singleton vaginal deliveries were retrospectively investigated to find frequency, risk factors and relation of episiotomy to third degree Perineal tears. To avoid the affect of confounding factors, we analyzed a sub-sample that included only vertex presentation with spontaneous occipito-anterior vaginal deliveries. Results: The incidence of episiotomy was 398. Third degree tears occurred in 1% of the deliveries with episiotomy in 0.2% of the deliveries without episiotomy. Third degree tears were more commonly occurred in primiparae, instrumental deliveries, episiotomy, and birth weight more than 4 kg. After stratification for birth weight and parity, no relation between episiotomy and third degree tear was found. Conclusion: In uncomplicated deliveries, no significant relation between third degree perineal tear and episiotomy was found.