Maternal HIV infection has been associated with adverse pregnancy outcomes, including stillbirth. We aimed to investigate the association between maternal HIV and stillbirths in the context of universal antiretroviral therapy (ART) during pregnancy in the Western Cape, South Africa.

We defined a cohort of pregnant women with documented HIV status and pregnancy outcome >20 weeks gestation enrolled in the Western Cape Pregnancy Exposure Registry from January 2017 - December 2021. Descriptive statistics and logistic regression analyses assessed proportion of stillbirths and odds ratios by HIV and ART status, and their relationship with clinical and demographic variables.

Among 15,123 pregnant women, HIV prevalence was 31.6% at pregnancy outcome (n=4,773) and 61.6% of women living with HIV (WLHIV) had started ART prior to pregnancy. Although stillbirths were higher among WLHIV: 17/1,000 births (95%CI:13.3-20.7; n=79) versus 14/1,000 births (95% CI:11.8-16.3; n=147) among women without HIV, HIV was not associated with stillbirth in multivariable analysis (aOR=1.2, 95% CI:0.9-1.5). Among WLHIV, ART duration ART≥100weeks had reduced odds of stillbirth compared to those on ART<20weeks (aOR=0.5, 95% CI: 0.3-0.9). Pre-existing diabetes was associated with stillbirth (aOR=2.6, 95% CI: 1.1-6.5).

In this cohort of pregnant women we found no differences in stillbirth rates between WLHIV and women without HIV but given the sample size and number of stillbirths, the study could not exclude small increases in risk. Longer ART duration was confirmed to be protective for stillbirth among WLHIV.