LONDON, ENGLAND -- March 26, 1999 -- Researchers in The Lancet this week report that delivery of babies by elective caesarean section significantly lowers the risk of mother-to-child transmission of HIV-1 infection compared with normal vaginal delivery.

Although there have been indications that caesarean section may reduce this risk, the study in this week's Lancet provides important evidence to confirm the efficacy of this mode of delivery. Hundreds of babies are born to HIV-1-infected mothers each year, so the researchers hope this finding will have a strong impact on clinical practice.

The study by the European Mode of Delivery Collaboration, which began in 1993 in Italy, involved centers throughout Europe. Although the trial is yet to be completed, an interim analysis provides information on 370 infants born to HIV-1 infected mothers.

To assess the effect of mode of delivery on the HIV-1 status of the baby, mothers were randomly assigned to delivery by elective caesarean section (done at 38 weeks) or vaginal delivery. Seven (3.4 percent) of the 203 infants who were delivered by caesarean section were infected with the HIV-1, compared with 15 (10.2 percent) of 167 infants born by normal vaginal delivery. This finding indicates that elective caesarean section delivery can reduce transmission of HIV-1 by more than half.

A baby can contract the HIV-1 virus from its mother both in the womb (in utero), when it is in contact with the maternal blood supply and during delivery. Prophylactic zidovudine decreases in utero transmission of the virus by reducing the amount of virus in the mother's blood and this drug is often given to pregnant women infected with HIV-1.

According to the investigators, elective caesarean section reduces the chance of transmission during delivery by avoiding direct contact with maternal vaginal secretions and infected blood during the infant's passage through the birth canal and reducing influx of maternal blood during uterine contractions.

Thanks to The Doctor's Guide to the Internet™ for the article