Foetal growth in pregnant women with HIV

Objective: Pregnant women with HIV (PWHIV) are at increased risk of delivering babies that are small for gestational age (SGA). We aimed to determine the foetal growth trajectories of PWHIV, compared to HIV-negative women.

Design: Prospective pregnancy cohort study in Soweto, South Africa, in 2013–2016.

Methods: Serial ultrasound measurements (every 5 ± 1 weeks) of foetal head circumference, biparietal diameter (BPD), abdominal circumference and femur length were obtained from less than 14 weeks’ gestation to term. Multivariable linear mixed effects models were used to estimate differences in mean foetal growth measures [head circumference, BPD, abdominal circumference and femur length, and estimated foetal weight (EFW)] and mean foetal growth velocity increments (head circumference, BPD, abdominal circumference, and femur length) according to maternal HIV status. Z-scores and centiles were calculated according to the INTERGROWTH-21st standards for foetal growth. Multivariable mixed effects logistic regression was used to examine the association of maternal HIV infection with in-utero SGA (EFW <10th centile) and very SGA (VSGA, EFW <3rd centile).

Results: Ultrasound measurements of 228 PWHIV and 384 HIV-negative pregnant women, with a median of five antenatal ultrasound scans per women, were analysed. There were no significant differences in mean foetal growth measures of head circumference [−0.37 mm, 95% confidence interval (CI) −1.46 to 0.72], BPD (0.07 mm, 95% CI −0.45 to 0.30), abdominal circumference (0.15 mm, 95% CI −1.47 to 1.17), femur length (0.04 mm, 95% CI −0.27 to 0.34) and EFW (1 g, 95% CI 0.98–1.02), and growth velocity increments for head circumference (−0.07 mm/week, 95% CI −0.24 to 0.10), BPD (−0.01 mm/week, 95% CI −0.06 to 0.04), abdominal circumference (0.19 mm/week, 95% CI −0.06 to 0.44) and femur length (0.00 mm/week, 95% CI −0.04 to 0.04) between foetuses of PWHIV and HIV-negative women. The prevalence of SGA ranged between 14.2% and 26.4% for PWHIV and between 18.5% and 24.1% for HIV-negative pregnant women during different gestation windows. There was no significant association between maternal HIV infection and in-utero SGA [adjusted odds ratio (aOR) 0.90, 95% CI 0.54–1.52] or VSGA (aOR 1.16, 95% CI 0.55–1.54). A sensitivity analysis restricted to PWHIV who received efavirenz-based antiretroviral therapy (ART) yielded results consistent with the overall analysis.

Conclusion: Maternal HIV infection treated with ART does not appear to be associated with altered foetal growth, foetal growth velocity, or in-utero SGA, compared to HIV-negative women. Our findings support current international clinical guidelines recommending ART for PWHIV to improve maternal health and reduce vertical HIV transmission.