Caesareans Help Protect Babies From AIDS
The risk that an HIV-infected woman will pass the virus to her baby during birth is nearly eliminated if she takes a standard AIDS drug and has a caesarean delivery, researchers have found.
The benefits of the AIDS drug AZT have been known for five years. The added advantage of a caesarean, however, was suspected but not proved until a large study--whose results were relesed Thursday--was completed.
The new data show that a caesarean cuts the risk of AIDS transmission in half. An infected woman who has a caesarean and AZT treatment has only about a 2% chance of infecting her child.
“All infected women need to be told about this information,” said Dr. Lynne Mofenson, a co-author of the study at the National Institute of Child Health and Human Development in Bethesda, Md.
The study is scheduled to be published in the March 31 issue of the New England Journal of Medicine. The journal posted the article early on the Internet because of its public health importance.
However, some of the information was released last summer at an AIDS meeting in Geneva, and as a result many obstetricians have already begun routinely scheduling caesareans for their HIV-infected patients.
The risk has already been sharply reduced in the industrialized world by giving AZT to women during pregnancy and by discouraging breast feeding, which also helps spread the disease.
The latest analysis was based on a compilation of 15 studies in North America and Europe involving 8,533 pairs of infected mothers and their children born between 1982 and 1996.
Among the key findings:
* With neither a caesarean nor AZT treatment, 19% of babies were born infected.
* If the mother got an elective caesarean but no AZT, 10% were infected.
* If she got AZT but no elective caesarean, 7% were infected.
* If she got both AZT and an elective caesarean, 2% were infected.
The researchers believe that about 70% of AIDS transmission from mother to child occurs during the birth process, rather than while the fetus is in the womb. They theorize that caesareans protect babies two ways:
* The child is shielded from HIV-laden blood and secretions in the birth canal. During vaginal birth, the baby’s skin and mucous membranes are covered with these fluids, and the baby may also swallow them.
* During uterine contractions of labor, a small amount of blood is transferred from the mother’s circulation to the baby’s, and this too is avoided by an elective caesarean.
