Association between viral suppression during the third trimester of pregnancy and unintended pregnancy among women on antiretroviral therapy: Results from the 2019 antenatal HIV Sentinel Survey, South Africa

About half of the pregnancies among women living with HIV (WLWH) receiving antiretroviral therapy (ART) in sub-Saharan African countries are reported to be unintended. Unintended pregnancy is associated with late initiation of antenatal care (ANC), and may delay provision of viral load monitoring services, antenatal adherence counselling and support, and other services that promote sustained viral suppression throughout pregnancy. This study examines the association between unsuppressed viral load during the third trimester of pregnancy and unintended pregnancy among women who initiated ART before pregnancy. This was an analysis of data from a national antenatal survey conducted at 1 589 public health facilities in South Africa between 1 October and 15 November 2019. Consenting pregnant women aged 15-49 years attending ANC during the survey period were enrolled. Demographic and clinical data were collected through interview and medical record review. Pregnancy intention was assessed using two questions from the London Measure of Unplanned Pregnancy, and responses were categorized as "unintended," "undecided," and "intended." Blood specimens were collected from all women and tested for HIV; and if positive, a viral load test was performed. A survey domain-based poisson regression model examined the association between unsuppressed viral load during the third trimester of pregnancy and unintended pregnancy among women who initiated ART before pregnancy. Viral suppression was defined as viral load