Background: Perinatal transmission of human immunodeficiency virus (HIV) type 1 contributes significantly to infant mortality. Exposure in the birth canal may account for some transmission. We examined the efficacy of a birth canal washing procedure in reducing perinatal transmission in Malawi.
Methods: The infection status of infants of 3327 control women (conventional delivery procedures) was compared with that of 3637 infants of intervention-delivered women. The infants' HIV status was determined by polymerase chain reaction on dried blood spots collected at 6 and 12 weeks of age. The intervention consisted of manual cleansing of the birth canal with a cotton pad soaked in 0.25% chlorhexidine, which was done on admission in labour and every 4 h until delivery.
Findings: No adverse reactions to the intervention procedure were seen. 2094 (30%) of the enrolled women were HIV-infected, and 59% of their infants were seen in follow-up. Among 982 vaginal vertex singleton deliveries to HIV-infected women, 269 (27%) infants were infected. The intervention had no significant impact on HIV transmission rates (27% in 505 intervention women compared with 28% in 477 control women), except when membranes were ruptured more than 4 h before delivery (transmission 25% in the intervention group vs 39% in the control group).
Interpretation: If birth canal exposure is an important risk factor, different or additional methods to reduce the risk of perinatal HIV transmission should be tested. Alternatively, perhaps birth canal exposure is not a major contributor to perinatal infection risk.
PIP: In light of evidence that birth canal exposure to HIV may be a major means of maternal-fetal transmission of the infection, a clinical trial was performed to determine the safety and efficacy of cleansing the birth canal with a cotton pad soaked in 0.25% chlorhexidine. This cleansing took place on admission in labor and every four hours until delivery. After a pilot study in 160 women ensured the safety of the procedure, the study was designed so that all women giving birth in June, July, and November 1994 were part of the control group and those giving birth from August to October were assigned to the intervention group. The mother's HIV status was established, and infants were seen at 6 and 12 weeks postpartum. After adjustment of the sample, data were analyzed on 3327 controls and 3637 cases. 2094 of the total enrolled were infected with HIV. Of these, 59% brought their infants to follow-up at least once as did 61.5% of the mothers who were not infected. The mother-to-infant transmission rate in this study was 27.4%. There was no evidence that the intervention prevented transmission. The only case in which washing reduced transmission rates was in babies born to women whose membranes were ruptured for more than four hours before delivery (in these, the transmission rate was significantly lower in intervention women [25%] than in control women [39.4%]). This result points to a role for ascending infection, but, if this were the case, washing before rupture of the membranes should have and did not reduce risk. Possible reasons for the failure of this intervention are that there may have been inadequate cleansing, the chlorhexidine solution may have been too weak, or the role of birth canal exposure in transmitting the infection may be less than previously believed. It is also difficult to quantify peripartum transmission in infants who are breast fed. The multiple modes by which infection may be transmitted will make it difficult to discover a simple, effective, and affordable way to reduce maternal-child transmission in developing countries.