PREGNANT women with HIV can virtually eliminate the risk of passing the virus
to their child if they take the drug AZT and also have a Caesarean delivery.
Researchers at 85 French hospitals studied the births of nearly 3000 children
to see whether the type of delivery influenced AZT鈥檚 ability to prevent HIV
passing from mother to child. A total of 133 women took AZT during their
pregnancy and had a Caesarean section before their membranes ruptured and labour
began. Just one of their babies was born infected with HIV鈥攁 transmission
rate of 0.8 per cent, the researchers report this week in the Journal of the
American Medical Association (vol 280, p 55). Of the 769 women who were
taking AZT and had a normal delivery, 6.6 per cent of their babies were
infected.
Doctors already knew that AZT during pregnancy slashed mother-to-child
transmission of HIV by two-thirds
(This Week, 5 April 1997, p 6). The new study
suggests that a Caesarean could further cut transmission by almost 90 per cent.
鈥淭his is a very, very important finding,鈥� says Alain Berrebi of the Hospital de
la Grave in Toulouse, one of the obstetricians involved in the study. In the
absence of AZT, however, a Caesarean had little effect on HIV transmission.
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Stephane Blanche of the Necker Hospital in Paris, who also worked on the
study, says that Caesareans probably protect babies from exposure to HIV in
genital secretions and maternal blood during birth. But why this only works in
conjunction with AZT is unclear.
Diana Gibb of the Medical Research Council鈥檚 HIV Clinical Trials Unit in
London expects the new findings to have an immediate impact on obstetric
practice for women who are HIV-positive. 鈥淭here are going to be more Caesarean
sections,鈥� she says.