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

Abstract

Objectives: 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.

Methods: 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 <50 copies/mL.

Results: Of 10 901 WLWH with viral load data available, 63.3% (95% confidence interval (CI): 62.4%-64.1%) were virally suppressed. Among the 2 681 women (representing 24.1% of all WLWH with viral load data) who initiated ART before pregnancy and were in their third trimester at the time of enrolment, 74.4% (95% CI: 73.0%-75.8%) were virally suppressed. In the same population, the proportion virally suppressed was lower among women whose current pregnancies were unintended (72.1%, 95% CI: 70.1%-74.1%) compared to women whose pregnancies were intended (78.3%, 95% CI: 75.9%-80.5%). In multivariable analyses adjusted for age, gravity, marital status, education, location of facility and syphilis status, unintended pregnancy was associated with unsuppressed viral load during the third trimester (adjusted relative risk: 1.3, 95% CI: 1.1-1.4) among women who initiated ART before pregnancy.

Conclusion: The identified association between unsuppressed viral load and unintended pregnancy among pregnant women who initiated ART before pregnancy highlights the need to strengthen routine assessment of fertility preferences and provision of contraceptive services to reproductive age WLWH receiving ART.

Fig 1. Flow chart of observations excluded from the analysis, the 2019 antenatal HIV Sentinel Survey, South Africa.