['To investigate whether Thai HIV-1-infected pregnant women require a dose increase of lopinavir/ritonavir (LPV/r) and to assess the safety and efficacy of the generic tablets during pregnancy.', 'Prospective, single-center pharmacokinetic study.', 'HIV-infected pregnant, antiretroviral therapy-naive or experienced women started HAART containing generic LPV/r 400/100 mg tablets twice daily. The 12-h pharmacokinetic curves were recorded at gestational age 20 weeks (GA20, optional), 33 weeks (GA33) and 12 weeks postpartum (12PP, optional).', 'Twenty women were included. Median [interquartile range (IQR)] age was 28 (25-33) years and mean (SD) weight at GA33 was 59.9 (4.2) kg. Mean (SD) values for LPV area under the curve(0-12 h), C(max), C(min), and T(half) were 72.9 (19.2) mg/l h, 9.3 (2.2) mg/l, 3.2 (1.3) mg/l and 4.8 (2.4) h, respectively, on GA33 and 98.0 (24.1) mg/l h, 11.7 (2.2) mg/l, 4.7 (2.2) mg/l and 5.9 (2.7) h, respectively on 12PP. Twelve women recorded both GA33 and 12PP curves; mean LPV AUC(0-12) was significantly lower at GA33 [-24.1 (95% confidence interval -44.4 to -3.7) mg/l h]. At GA33, 19 of 20 women had sufficient LPV trough concentrations (>1.0 mg/l) and at 12PP, all had sufficient LPV trough concentrations. None of the women stopped LPV/r before planned discontinuation due to side-effects. At delivery, 19 of 20 women had a viral load below 50 copies/ml. One woman had a viral load of 60 copies/ml, but was undetectable at 12PP.'] Do thai HIV-1-infected women require a dose increase of lopinavir/ritonavir during the third trimester of pregnancy?