A cohort of 297 HIV-infected pregnant women was followed from January 1996 to December 2001. The overall transmission rate was 3.57% and remained constant over time. Low birth-weight was independently associated with a higher risk of vertical transmission (P=0.0072), whereas a longer duration of antiretroviral drugs during pregnancy was independently associated with a lower risk of transmission (P=0.0084). Further decreases in transmission should be obtained by initiating prophylaxis earlier in pregnancy.

Few studies have compared the clinical efficacy and adverse events of combined antiretroviral therapy (cART) regimens in pregnant women seeking obstetrical care. The objective of this study was to compare the efficacy (virus load response), adverse events and obstetrical and neonatal outcomes of three different regimens of cART in HIV-infected pregnant women initiating treatment in Rio de Janeiro, Brazil. This was a retrospective cohort study of cART- naïve pregnant women who initiated either ritonavir boosted protease inhibitors (atazanavir or lopinavir), efavirenz, or raltegravir plus a backbone regimen. From 2014 to 2018, 390 pregnant women were followed over time. At baseline, median HIV viral load was 4.1 log copies. Among participants who received cART for 2-7 weeks, the virus load (VL) decline was greater for raltegravir (2.24 log copies), as compared to efavirenz or protease inhibitors (p < 0.001). Virologic suppression was achieved in 87% of women on raltegravir near delivery versus 73% on efavirenz and 70% on protease inhibitors (p = 0.011). Patients on raltegravir achieved virologic suppression faster than those on other regimens (p = 0.019). Overall the HIV perinatal infection rate was 1.5%. This clinical study compared three potent and well tolerated cART regimens and demonstrated that a higher proportion of participants on raltegravir achieved an undetectable HIV VL near delivery (p=0.011) as compared to the other arms. These findings suggest that raltegravir-containing regimens are optimal regimens for women with HIV initiating treatment late in pregnancy.