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