Differences in perineal lacerations in black and white primiparas

Objective: To test the null hypothesis that there are no differences in inc idence of perineal and vaginal lacerations in primiparous black and white w omen. Methods: We reviewed University of Michigan Hospital delivery records, from July 1996 to December 1998, of black and white women 18 years and older an d at least 35 weeks' gestation who had their first vaginal delivery. Birth weight, episiotomy, gestational age, laceration, length of second stage, ox ytocin use, epidural use, and operative vaginal delivery were analyzed by u nivariable and multivariable tests. Results: We analyzed 176 black women (mean age a standard deviation 23.7 +/ - 4.7 years; range 18-41 years) and 1633 white women (27.8 +/- 5.4 years; 1 8-49 years; P <.001). Black women were less likely to have second, third, o r fourth degree lacerations (43% compared with 59%; P <.001). The mean leng th of second stage of labor was shorter in the black women (73 +/- 69 minut es; range 3-494 minutes compared with 106 +/- 78 minutes; range 2-642 minut es; P <.001). infants of black women weighed less (3292 +/- 490 g; 1990-519 0 g compared with 3429 +/- 470 g; 1860-4953 g; P <.001). Multivariable anal ysis showed that black women were twice as likely to deliver with intact pe rineums than white women (P <.001). Conclusion: Black primiparas were less likely to deliver with second-degree or greater lacerations and more likely to deliver with their perineums int act. (Obstet Gynecol 2000; 96:622-4. (C) 2000 by The American College of Ob stetricians and Gynecologists.).