Urine pregnancy tests were performed at screening and
quarterly follow-up visits for HIV-1-infected women.
For HIV-1-uninfected women, urine pregnancy tests
were done on the basis of the report of missed menses.
Date of last menstrual period (LMP), estimated date of
delivery, and pregnancy outcome were collected for all
pregnancies. We defined the start of pregnancy as the date
of LMP and the end of pregnancy as the date of delivery
or pregnancy loss.
Complete data on LMP and date of
delivery were available for 96% of pregnancies observed
during the study; for the remaining 4% of pregnancies
that were missing either of these parameters, we estimated
start and end dates using the reported duration of the
pregnancy (based on maternal history) and either LMP
or date of delivery.
We defined HIV-1-uninfected
women and male partners of HIV-1-infected women
as ‘pregnancy exposed’ during the period between LMP
and 6 weeks following the end of pregnancy, thus
including the early postpartum period as pregnancyexposed time; inclusion of the early postpartum period is
consistent with other studies of pregnancy as a risk factor
for HIV-1 acquisition and reflects physiologic changes of
pregnancy that persist in the early postpartum period