Objectives: We assessed the association between the timing of pregnancy with the risk of postpartum virologic failure and loss from HIV care in South Africa.
Design: This is a retrospective cohort study of 6306 HIV-positive women aged 15-49 at antiretroviral therapy (ART) initiation, initiated on ART between January 2004 and December 2013 in Johannesburg, South Africa.
Methods: The incidence of virologic failure (two consecutive viral load measurements of >1000 copies/ml) and loss to follow-up (>3 months late for a visit) during 24 months postpartum were assessed using Cox proportional hazards modelling.
Results: The rate of postpartum virologic failure was higher following an incident pregnancy on ART [adjusted hazard ratio 1.8, 95% confidence interval (CI): 1.1-2.7] than among women who initiated ART during pregnancy. This difference was sustained among women with CD4 cell count less than 350 cells/μl at delivery (adjusted hazard ratio 1.8, 95% CI: 1.1-3.0). Predictors of postpartum virologic failure were being viremic, longer time on ART, being 25 or less years old and low CD4 cell count and anaemia at delivery, as well as initiating ART on stavudine-containing or abacavir-containing regimen. There was no difference postpartum loss to follow-up rates between the incident pregnancies group (hazard ratio 0.9, 95% CI: 0.7-1.1) and those who initiated ART in pregnancy.
Conclusion: The risk of virologic failure remains high among postpartum women, particularly those who conceive on ART. The results highlight the need to provide adequate support for HIV-positive women with fertility intention after ART initiation and to strengthen monitoring and retention efforts for postpartum women to sustain the benefits of ART.