Antiretroviral Therapeutic Drug Monitoring in HIV-Infected Pregnant Women: Maternal Immunovirological Outcome at Delivery and During the 18 Month Follow-Up Period

No data are available on the long-term immunovirological outcome of HIV-positive pregnant women experiencing sub–therapeutic antiretroviral drug (ARV) concentrations during pregnancy. The objective of our study was to assess the long-term virological outcome in pregnant women treated with HAART. A prospective, multi-center study enrolled 60 HIV-infected pregnant women stratified into 3 groups according to the response to HAART. Group A, women successfully treated with HAART; Group B, women with confirmed virological failure during HAART; Group C, women successfully treated with HAART during pregnancy for prevention of vertical transmission only. Smoking, alcohol use, low adherence to therapy, and increased viral load at delivery were significantly associated to virological failure at univariate analysis. At multivariate regression analysis, only adherence to therapy was reported as an independent variable related to the virological response (p <0.001). Virological failure during follow-up was reported in 2 (25.0%) of the 8 women with sub therapeutic Ctrough and in 4 of the 33 (12.1%) women with therapeutic Ctrough (p=0.33). In group C, the viro-immunological set points during follow-up did not differ from those observed before HAART initiation. No significantly increased rate of virological failure after delivery was reported in women with sub-therapeutic ARV concentrations during pregnancy and long-term follow-up. The long-term virological outcome was independently associated to reduced adherence to therapy. Evaluation of the clinical impact of the low plasma ARV concentrations during pregnancy on the long-term virological outcome deserves further larger studies.