BackgroundPoor adherence to antiretroviral therapy (ART) is associated with HIV disease progression and, during pregnancy, increased mother-to-child transmission risk. In Ukraine, access to combination ART is expanding but data on adherence are scarce.MethodsCross-sectional surveys of HIV-positive women were conducted i) at delivery (on antenatal ART adherence) and ii) during the first year postpartum (on ART adherence in the preceding four weeks). Factors associated with a score ≤11 on the self-report Case Adherence Support Evaluation (CASE) index or ≥1 self-reported missed dose were assessed using Fisher’s exact test.ResultsOf 185 antenatal participants and 102 postnatal participants, median ages were 27.5 and 29.5 years respectively: 28% (50/180) and 27% (26/98) reported an unplanned pregnancy, and 13% (24/179) and 17% (17/98) an illicit drug-use history (excluding marijuana). One quarter (49/180 antenatally, 27/101 postnatally) screened positive for depression. The proportion reporting ‘low’ ART-related self-efficacy (i.e. unable to do ≥1/5 ART-taking activities) was 20% (28/141) antenatally and 17% (11/66) postnatally. Antenatally, 14% (95% CI 10-21%) had a CASE score ≤11 and 35% (95% CI 28-42%) reported missing ≥1 dose. Factors associated with a CASE score ≤11 were unplanned pregnancy (25% (12/48) vs. 11% (13/120) where planned, p = 0.03) and living with extended family (23% (13/57) vs. 10% (12/125) living with partner/alone, p = 0.04). Self-report of ≥1 missed dose antenatally was additionally associated with younger age (p = 0.03) and lower self-efficacy (50% (14/28) reported ≥1 missed dose vs. 28% (30/108) of those with high self-efficacy, p = 0.04). Of 102 postnatal participants, 8% (95% CI 4-15%) had a CASE score ≤11 and 31% (95% CI 22-41%) reported ≥1 missed dose. Of 11 women with low self-efficacy, 3 (27%) had a CASE score ≤11 compared with 3/55 (5%) of those with high self-efficacy (p = 0.05). Current smokers more commonly reported ≥1 missed dose postnatally (50% (13/26) vs. 25% (18/72) of non-smokers, p = 0.03).ConclusionsOur results highlight unmet needs for counselling and support. We identify some groups at risk of poor ART adherence, including women with markers of social vulnerability and those with low ART-related self-efficacy, who may benefit from targeted interventions.