Résumé : Objective: To describe the pharmacokinetics of abacavir 600mg once daily (q.d.) in HIV-1-positive women during pregnancy and postpartum. Design: A nonrandomized, open-label, multicentre, phase-IV study. Methods: HIV-positive pregnant women receiving abacavir 600mg q.d. as part of clinical care were included. Intensive 24-h pharmacokinetic sampling was performed during the third trimester and at least 2 weeks after delivery. Pharmacokinetic parameters were calculated by noncompartmental analysis. Paired cord blood and maternal blood samples were taken at delivery when feasible. Results: A total of 14 women were included in the analysis. Geometric mean ratios (90% confidence intervals) of third trimester versus postpartum were 1.05 (0.92-1.19) for AUC 0-24h and 1.00 (0.83-1.21) for C max. The median (range) ratio of abacavir cord plasma to maternal plasma was 1.0 (0.7-1.0, n=3). Viral load at the third trimester visit was less than 50copies/ml in 13 participants (93%; one unknown). In total, 13 (93%; one unknown) children were tested HIV-negative. Conclusion: The pharmacokinetics of abacavir 600mg q.d. during pregnancy are equivalent to postpartum. No dose adjustments are required during pregnancy and similar antiviral activity is expected.