BREAST-FEEDING, GENETIC, OBSTETRIC AND OTHER RISK-FACTORS ASSOCIATED WITH MOTHER-TO-CHILD TRANSMISSION OF HIV-1 IN SAO-PAULO STATE, BRAZIL

Objectives: To evaluate the effect of maternal, obstetric, neonatal an d post-natal factors on the risk of vertical transmission of HIV-1. De sign: Multicentre retrospective cohort study. Setting: Obstetric and p aediatric clinics in four cities in Sao Paulo State, Brazil. Main outc ome: Child's HIV-1 infection status. Methods: Data were collected by s tandardized record abstraction and interview on 553 children born to w omen identified as HIV-1-infected before or at delivery. Paediatric in fection was determined by immunoglobulin G anti-HIV-1 tests at age 18 months or by AIDS diagnosis at any age. Multivariate logistic regressi on was used to assess the effect of potential risk factors on vertical transmission of HIV-1. Results: HIV-1 infection status was determined for 434 children (follow-up rate of 78%); 69 were classified as HIV-1 -infected [transmission risk, 16%; 95% confidence interval (CI), 13-20 %]. In multivariate analysis, advanced maternal HIV-1 disease [odds ra tio (OR), 4.5; 95% CI, 2.1-9.5], ever breastfed (OR, 2.2; 95% CI, 1.2- 4.2), child's negative Rhesus blood group (OR, 2.5; 95% CI, 1.2-5.5), third trimester amniocentesis (OR, 4.1; 95% CI, 1.2-13.5) and black ra cial group (OR, 0.3; 95% CI, 0.1-0.9) were independently and significa ntly associated with mother-to-child transmission of HIV-1. Transmissi on was increased marginally with prematurity, more than 10 lifetime se xual partners and prolonged duration of membrane rupture. No associati on was found between child's HIV-1 infection and mode of delivery or s erological evidence of syphilis during pregnancy. Conclusion: These fi ndings support the importance of severity of maternal HIV-1 disease in the risk of vertical transmission of HIV-1, indicate measures to redu ce transmission by avoiding amniocentesis and breastfeeding and sugges t that race and Rhesus blood type may be markers for genetic susceptib ility to infection. (C) 1998 Rapid Science Ltd.