Determinants of suboptimal adherence and elevated HIV viral load in pregnant women already on antiretroviral therapy when entering antenatal care in Cape Town, South Africa

Across sub-Saharan Africa, prevention of mother-to-child transmission services are encountering increasing numbers of women already established on antiretroviral therapy (ART) when entering antenatal care. However, there are few data examining ART adherence and HIV viral load in this group. We used multivariable logistic regression models to examine self-reported suboptimal adherence (defined as missed ART doses on >= 2 days during the preceding 30 days), elevated viral load (>= 1000 copies/mL), and factors associated with each among women entering antenatal care on ART. Participants were recruited from one primary care clinic in Gugulethu, Cape Town, as part of a larger study of HIV-positive pregnant and postpartum women. Among 482 pregnant women established on ART and enrolled between May 2013 and June 2014 (median age: 31 years; median duration of ART use: 3 years), 15% reported suboptimal adherence and 12% had elevated viral load. After adjustment for age, suboptimal adherence was significantly more common among women who were not married/cohabiting and women who reported a higher level of concern about taking ART; a higher level of adherence self-efficacy was associated with a reduced odds of suboptimal adherence. In a multivariable model, elevated viral load was significantly associated with previous discontinuation of ART, a higher level of concern about taking ART, and report of an unintended pregnancy. Suboptimal adherence and elevated viral load are common among women entering antenatal care already on ART. Our findings highlight specific beliefs and concerns about ART use during pregnancy that should be addressed in counselling messaging, and suggest that family planning should be more effectively integrated into HIV care. Including adherence and viral load monitoring as part of pregnancy planning for women on ART may be important to achieve safer conception and promote healthy pregnancies.