HETEROSEXUAL BEHAVIOR DURING PREGNANCY AND PERINATAL TRANSMISSION OF HIV-1

Objective: To determine the relationship between maternal heterosexual activity during pregnancy and perinatal transmission of HIV-1. Design : A retrospective analysis of 175 New York City HIV-1-seropositive wom en enrolled during pregnancy or immediately post-partum from 1986 to 1 994 in a prospective cohort study. Methods: Frequency of heterosexual intercourse and condom use during pregnancy was determined from self-r eport measures. Unprotected intercourse was defined as follows: 'none' , consistent condom use or abstinence; 'moderate', inconsistent condom use and fewer than 80 episodes of intercourse; and 'high', inconsiste nt condom use and 80 or more episodes. Results: The rate of perinatal HIV-1 transmission was 9.1% (four out of 44) among women with no unpro tected intercourse during pregnancy, 22.2% (20 out of 90) among those with moderate frequency, and 39.0% (16 out of 41) among those with hig h frequency (P < 0.01). The relative risk (RR) of perinatal transmissi on was higher among women with moderate [RR, 2.4; 95% confidence inter val (Cl), 0.9-6.7] and high frequency of unprotected sexual intercours e (RR, 4.3; 95% Cl, 1.6-11.8) compared with women with no unprotected sexual intercourse. When potential covariates (maternal injecting drug use, CD4 lymphocyte count, AIDS, zidovudine use, pelvic inflammatory disease or sexually transmitted disease during pregnancy, delivery mod e, and extreme prematurity) were included in a logistic regression mod el (n = 128), the rate of perinatal transmission remained significantl y higher among women with any unprotected sexual intercourse during pr egnancy. Conclusions: Data suggest that unprotected sexual intercourse during pregnancy influences perinatal HIV-1 transmission.