Third trimester vitamin D status is associated with birth outcomes and linear growth of HIV-exposed uninfected infants in the United States.

Background: Vitamin D status in pregnancy may influence the risk of prematurity, birth size, and child postnatal growth, but few studies have examined the relationship among pregnant women living with HIV. Methods: We conducted a prospective cohort study of 257 HIV-infected mothers and their HIV-exposed uninfected infants who were enrolled in the 2009-2011 nutrition substudy of the Surveillance Monitoring for ART Toxicities (SMARTT) study. HIV-infected pregnant women had serum 25-hydroxyvitamin D (25(OH) D) assessed in the third trimester of pregnancy, and their infants' growth and neurodevelopment were evaluated at birth and approximately 1 year of age. Results: The mean third trimester serum 25(OH) D concentration was 35.4 +/- 14.2 ng/mL with 15% of women classified as vitamin D deficient (< 20 ng/mL) and 21% as insufficient (20-30 ng/mL). In multivariable models, third trimester vitamin D deficiency and insufficiency were associated with 2273 g [95% confidence interval (CI): 2450 to 297] and 2203 g (95% CI: 2370 to 235) lower birth weights compared with vitamin D sufficient women, respectively. Maternal vitamin D deficiency was also associated with shorter gestation (mean difference 20.65 weeks; 95% CI: 21.22 to 20.08) and lower infant length-for-age z-scores at 1 year of age (mean difference: 20.65; 95% CI: 21.18 to 20.13). We found no association of vitamin D status with infant neurodevelopment at 1 year of age. Conclusion: Third trimester maternal vitamin D deficiency was associated with lower birth weight, shorter length of gestation, and reduced infant linear growth. Studies and trials of vitamin D supplementation in pregnancy for women living with HIV are warranted.