Poster No. P_90. Birth weight and preterm delivery outcomes of perinatally vs. non-perinatally HIV-infected pregnant women in the U.S.: results from the PHACS SMARTT study and IMPAACT P1025 protocol
Background: The success of antiretroviral therapy (ART) has resulted in many perinatally HIV-infected (PHIV) youth reaching reproductive age. Pregnancy outcomes of PHIV women compared to women acquiring HIV non-perinatally (nPHIV) are poorly defined. Methods: We compared birth weight (BW) and preterm delivery (PTD) outcomes of PHIV versus nPHIV pregnant women enrolled in the PHACS Surveillance Monitoring for ART Toxicities Study (SMARTT) or IMPAACT P1025 protocol. Women were 13-30 years old. Infants were HIV-uninfected singleton liveborns. Maternal PHIV status was identified by self-report, medical record review, or HIV infection documented within 5 years of birth. BW z-scores (BWZ) and small-for-gestational-age (SGA) were calculated using U.S. standards. Mixed effects models were applied to assess the association of maternal PHIV status with infant BWZ; log binomial models using generalized estimating equations were fit for PTD (delivery at < 37 weeks) and SGA outcomes. Results: From 1998-2013, 2,270 HIV-infected pregnant women delivered 2,692 newborns (270 born to PHIV and 2,422 to nPHIV women). Compared to nPHIV women, PHIV women were younger (mean age 21 vs. 25 years, p< 0.01) and less often Black (55% vs. 67%, p< 0.01). PHIV women were more likely to have a CD4 count < 200 cells/mm³ during pregnancy (19% vs. 11%, p=0.01), delivery HIV RNA level ≥400 copies/mL (28% vs. 23%, p< 0.01), receipt of ≥3-class ART during pregnancy (23% vs. 2%, p< 0.01), and pre-pregnancy body mass index (BMI) < 18.5 kg/m² (6% vs. 3%, p< 0.01). PHIV were less likely to report tobacco (14% vs. 20%, p=0.01) and substance use (1.7% vs. 3.3%, p< 0.01) during pregnancy. After adjustment, BWZ was 0.13 lower in infants of PHIV vs. nPHIV women (adjusted mean: -0.46 vs. -0.33, p=0.03). Black race, tobacco and substance use in pregnancy, and maternal pre-pregnancy BMI < 18.5 kg/m² were also significantly associated with lower infant BWZ. No associations between maternal PHIV status and PTD or SGA were observed. Conclusions: Infants of PHIV versus nPHIV women may be at greater risk for lower BW, although the absolute difference was small. Future studies are warranted to understand mechanisms by which the intrauterine environment of PHIV women may affect fetal growth.