Antiretroviral therapy during pregnancy and risk of preterm birth

BackgroundAntiretroviral therapy use in pregnancy, and specifically regimens containing protease inhibitors (PIs), has been associated with adverse infant outcomes including preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA) infants. However, there are conflicting results in the literature with respect to the degree of risk. These results may be related to demographic factors and confounding of maternal HIV infection and degree of immune suppression.ObjectiveThe primary objective of our study was to assess the risk of PTB in HIV-positive pregnant women on ART compared to HIV-negative pregnant women. Secondary objectives included: comparing the risks of LBW and SGA infants in HIV-positive women on ART to HIV-negative pregnant women; comparing the risks of PTB, LBW and SGA in HIV-positive women on PI-based regimens compared to HIV-negative women.MethodsA retrospective matched cohort study of 384 women was conducted between 2007 and 2012 comparing outcomes of HIV-positive women on ART to HIV-negative women. Univariate and multivariable logistic regression models were used, adjusting for potential confounding factors, to compare the two groups on adverse infant outcomes.ResultsUnadjusted odds ratios revealed a >2-fold increase in rates: PTB OR 2.6 [95% CI 1.3-5.1]; LBW OR 2.9 [95% CI 1.4-6.3]; SGA OR 2.5 [95% CI 1.3-4.7]. Once odds ratios were adjusted to account for race (p < 0.01), our results were no longer statistically significant as this study was underpowered to detect smaller differences: PTB aOR 1.4 [95% CI 0.5-3.6]; LBW OR 1.9 [95% CI 0.6-5.5]; SGA OR 1.8 [95% CI 0.8-4.6].ConclusionOur preliminary results show an increase in PTB, LBW and SGA but due to lack of power, our adjusted results are not statistically significant. A larger prospective follow-up study is needed to further explore these findings in this population.