Perinatal transmission of HIV virus: Risk factors

Objective: To investigate the role of different risk factors taking into account the effect of some potentially confounding variables. Methods: Data about maternal risk factors (clinical stage; CD4+ lymphocytes number, P24 antigenaemia, way of maternal infection, bleeding during pregnancy) and about events connected with delivery (gestational age, scalp, episiotomy) were collected from 519 mothers and 528 children born between 1 January 1987 and 31 December 1991. Infants were observed at least to the age of 18 months. The infection status of infants and mothers was assessed according to the CDC criteria. The CHI-SQUARE test was used for univariate analysis. Multiple logistic regression was performed to measure the effect of the potentially confounding variables using the odds ratio as the association measure. Results: Mothers at IV CDC stage, with CD4+ counts below 500/mm³ and P24 antigenaemia were more at risk of transmitting infection to their children born after. As regards the way of delivery, children born by vaginal delivery or emergency Cesarean seem to be more frequently infected (20%) than those born by elective Cesarean (10.8%), but the result was not statistically significant but in multivariate analysis the probability of infection in children delivered by elective Cesarean was 3.25 (C.I. 0.70-15.20) times that of children delivered by emergency Cesarean or 3.23 (C.I. 1.15-9.06) times that of children delivered vaginally. Conclusion: Our data suggest that mothers at IV CDC stage, with CD4+ counts below 500/mm³ and P24 antigenaemia were more at risk of transmitting infection to their children and that elective Cesarean section may have a protective effect, either compared with emergency Cesarean section or with vaginal delivery.