RESUMEN
INTRODUCTION: Success in addressing prevention of mother-to-child transmission of HIV depends largely on good adherence to anti-retroviral therapy (ART) by pregnant women. Knowledge of the levels of ART adherence among pregnant women is essential to inform strategies to prevent or reduce HIV transmission rates, particularly in African settings. Aim: the primary objective of this study was to measure adherence to anti-retroviral therapy (ART) among pregnant women living with human immunodeficiency virus (HIV). The secondary objectives were to determine: i) the rate of new infections among children at Mabote Filter Clinic in Maseru, Lesotho whose mothers were enrolled in PMTCT, and ii) the factors associated with non-adherence to ART among pregnant women. METHODS: In this prospective cohort study, HIV-positive pregnant women receiving antiretroviral therapy (ART) for prevention of mother to child transmission (PMTCT) were followed up to delivery and their children were tested for HIV. We collected socio-demographic information, knowledge of PMTCT and adherence to ART (three-day recall and pill count) including reasons for non-adherence. We also used logistic regression to explore factors associated with non-adherence. RESULTS: One hundred and seven women were included. The mean (standard deviation) age of the participants was 28.2 (5.7) years. Most, 81.3% (87/107), were married, only 9.3% (10/107) had a postsecondary education. Two-thirds (63.6%: 68/107) of the participants started ART because of PMTCT. Only 78.5% (84/107) of the participants had adequate knowledge of the importance of PMTCT. The three-day self-reported non-adherence rate at the first visit was 7.5% (95% confidence interval (CI): 3.7, 13.1), but up to 43.4% (95% CI: 35.2, 51.9) using pill count. The most frequently reported reasons for not adhering were: running out of pills (7.5%), nausea (5.6%) and to avoid side-effects (3.7%). Women who were employed (odds ratio (OR) 4.35; 95% CI: 1.38,14.29; p = 0.012) and at a higher gestational age (OR = 1.43; 95% CI: 1.11, 1.85; p = 0.006) were more likely to be non-adherent. Only 1 of the 77 exposed infants was found to be positive for HIV at 6 weeks after birth. CONCLUSION: We found a higher non-adherence rate for participants with pill count compared to a three-day adherence self-report. However, mother to child HIV transmission was relatively low. Lack of employment and relatively high gestational age were found to be predictive factors of non-adherence.