Background:  Since the  results of PACTG 076 documented the reduction in HIV-1 perinatal transmission, many advances have been made in the treatment and monitoring of infected pregnant women. Objectives were to describe epidemiological and clinical features of HIV-infected pregnant women  on follow-up at one multidisciplinary HIV perinatal clinic.

Methods: To compare HIV transmission rates according to antiretroviral therapy (ARV) and mode of delivery, we reviewed the charts of 363 infected pregnant women in follow-up at our unit from April 1994 to August 2003. Data on the relationship between time on pregnancy and the diagnosis of HIV infection, ARV treatment, type of delivery and newborn HIV infection status were collected

Results:  Complete data were obtained from 349 patients. Mean age was 26.8 years . Previous AIDS defining events were found in 12.6% of cases . Mean viral load and CD4⁺ cell count were 3.61 log₁₀ copies/mL and 415 cells/mm³.Risk factor for HIV infection was sexual exposure in 67% of cases. The proportion of patients with diagnosis of HIV during pregnancy decreased from 60% (1994-2000) to 27%  (2001-2003) and since 1997 more than 75% received any ARV treatment. For the analysis of the transmission rate aborts (8), fetal deaths (6), and unknown or pending newborn HIV status cases (42) were excluded.  Type of delivery was vaginal in 168 (59%), caesarean in 117 (41%),  88 electives (EC) and 29 non-electives (NEC); 241 patients received ARV and 52 no therapy (n = 293). Type of treatment was 32% complete ACTG 076 (94/293), 8.19% incomplete ACTG 076  (24/293), 42% combined therapy  (123/293; 51 2NRTI, 35  + 1 NNRTI, 37 + 1 PI), and 17.7% no treatment (52/293).  Of 293 newborns, 28 were infected (global transmission rate: 9.55%). Transmission rates according to type of delivery were vaginal 9.52% (16/168), EC 6.81% (6/88), and NEC 17.24% (5/12). Relationship between transmission rate and ARV therapy was:  4.24%  complete ACTG 076 (4/94), 20.83% incomplete ACTG 076 (5/24),  36.5% no treatment (19/52), and  0% combined therapy (1 vs 4, p <0.016;   2 vs 4,  p < 0.0039; any group vs 3, p <0.0001).

Conclusions:  The proportion of patients with known HIV status who become pregnant is increasing.  Prophylaxis with ZDV decrease rate of HIV transmission even though it is incomplete. Combined antiretroviral therapy improves efficacy of  monotherapy to reduce perinatal HIV transmission, irrespective of type of delivery.

Keywords: perinatal; transmission; strategies