Being Alive 1994 Mar 5: 14
The National Institutes of Health (NIH) stopped a clinical trial (ACTG
076) investigating whether giving AZT to pregnant HIV-infected women
during pregnancy and labor and to newborns for six weeks after birth
would reduce the proportion of babies born with HIV.
Participants were HIV+ pregnant women who had received no
antiretroviral treatment during the current pregnancy and had no clear
clinical indication to do so and had a CD4 less than 200. They were
randomized to receive AZT or placebo beginning between 14 and 34 weeks
of pregnancy. The AZT regimen consisted of 500 mg/day until the start
of labor, then IV AZT during labor, then a syrup form given to the
newborn for six weeks. The infants were evaluated at 12, 24 and 78
weeks after birth to see if HIV could be cultured from their blood.
Of the 364 babies with sufficient data to be evaluated, 13 (8.3%) in
the AZT group vs. 40 (25.5%) in the placebo arm were HIV infected.
Thus, the use of AZT in this particular group reduced the risk of
mother-to-infant transmission by 67.5%. Side effects were equal in
both groups, except that the babies in the AZT group had a higher
incidence of a mild anemia at birth, which disappeared gradually
without requiring transfusion. The rate of congenital malformations
was also equal and the same as the normal rate in the population, and
there were no adverse effects on the mothers in either group.
The typical risk of mother-to-infant HIV transmission in the US is
from 20-25%. The potential reduction to about 8% is obviously exciting
We must be careful to remember that the results are directly
applicable only to women similar to those in this trial. In
particular, the long term risks of the AZT use, including in the HIV
negative infants, remains to be assessed. It is important that
everyone be followed for a long time.There is also danger that these
results will be taken as evidence for mandatory HIV antibody testing
of all pregnant women, and even the mandatory use of AZT. We must be
vigilant to fight any such proposals.