Does HIV infection modify the relationship between pre‐pregnancy body mass index and adverse birth outcomes?. Issue 6 (3rd June 2020)

• Record Type: Journal Article
• Authors: Bengtson, Angela M.; Phillips, Tamsin K.; le Roux, Stanzi M.; Brittain, Kirsty; Zerbe, Allison; Madlala, Hlengiwe; Malaba, Thokozile; Petro, Gregory; Abrams, Elaine J.; Myer, Landon
• Is Part Of: Paediatric and perinatal epidemiology. Volume 34:Issue 6(2020:Nov.)
• Page Start: 713
• Page End: 723
• Publication Date: 2020-06-03
• Subjects: body mass index -- HIV -- obesity -- pregnancy -- pregnancy outcome; Pediatrics -- Periodicals; Perinatology -- Periodicals; Pediatric epidemiology -- Periodicals; Infants (Newborn) -- Diseases -- Periodicals; 618.92
• DOI: 10.1111/ppe.12688
• Languages: English
• ISSNs: 0269-5022

Abstract

Abstract: Background: South Africa faces dual epidemics of HIV and obesity; however, little research has explored whether HIV status influences associations between pre‐pregnancy body mass index (BMI) and adverse birth outcomes. Objectives: To examine associations between pre‐pregnancy body mass index (BMI) and adverse birth outcomes, and if they differ by HIV status. Methods: We followed HIV‐uninfected and ‐infected pregnant women initiating antiretroviral therapy (ART) from first antenatal visit through delivery. HIV‐infected women initiated ART (tenofovir‐emtricitabine/lamivudine‐efavirenz) in pregnancy. Estimated pre‐pregnancy BMI (kg/m 2 ) was categorised as underweight (<18.5), normal (18.5‐24.9), overweight (25.0‐29.9), and obese (≥30.0). We used modified Poisson regression to estimate risk ratios (RR) for associations between pre‐pregnancy BMI and adverse birth outcomes and explored modification by HIV status. Results: Among 1116 women (53% HIV‐infected), 44% of HIV‐uninfected women and 36% of HIV‐infected women were classified as obese; 4% of women were underweight. Overall, 12% of infants were delivered preterm (<37 weeks), 10% small for gestational age (SGA, <10th percentile), and 9% large for gestational age (LGA, >90th percentile). Compared to HIV‐uninfected women, HIV‐infected women on ART had less LGA (5% vs 13%) but more SGA (12% vs 8%), and a similar proportion of preterm (13% vs 11%) infants. Pre‐pregnancy BMI was not associated with preterm birth. Among HIV‐uninfected women, obesity modestly increased the risk of LGA (RR 1.34, 95% confidence interval [CI] 0.82, 2.19), and underweight modestly elevated the risk of SGA (RR 1.66, 95% CI 0.79, 3.46). These associations were attenuated among HIV‐infected women (RR 1.07, 95% CI 0.44, 2.64 for LGA, and RR 1.34, 95% CI 0.49, 3.64 for SGA). Conclusions: In this urban African setting of high HIV prevalence, pre‐pregnancy obesity was common and did not vary by HIV status. In HIV‐uninfected women, obesity increased the risk of LGA and being underweight the risk of SGA, compared with among HIV‐uninfected women.