Differences in perineal lacerations in black and white primiparas

To test the null hypothesis that there are no differences in incidence of perineal and vaginal lacerations in primiparous black and white women.

We reviewed University of Michigan Hospital delivery records, from July 1996 to December 1998, of black and white women 18 years and older and at least 35 weeks' gestation who had their first vaginal delivery. Birth weight, episiotomy, gestational age, laceration, length of second stage, oxytocin use, epidural use, and operative vaginal delivery were analyzed by univariable and multivariable tests.

We analyzed 176 black women (mean age +/- standard deviation 23.7 +/- 4.7 years; range 18-41 years) and 1633 white women (27.8 +/- 5.4 years; 18-49 years; P <.001). Black women were less likely to have second, third, or fourth degree lacerations (43% compared with 59%; P <.001). The mean length of second stage of labor was shorter in the black women (73 +/- 69 minutes; range 3-494 minutes compared with 106 +/- 78 minutes; range 2-642 minutes; P <.001). Infants of black women weighed less (3292 +/- 490 g; 1990-5190 g compared with 3429 +/- 470 g; 1860-4950 g; P <.001). Multivariable analysis showed that black women were twice as likely to deliver with intact perineums than white women (P <.001).

Black primiparas were less likely to deliver with second-degree or greater lacerations and more likely to deliver with their perineums intact.