Effect of Vitamin A status during pregnancy on maternal anemia and newborn birth weight: results from a cohort study in the Western Brazilian Amazon

Purpose Inadequate Vitamin A (VA) status during pregnancy has been associated with maternal anemia and suboptimal newborn birth weight (BW). We assessed the effect of gestational serum retinol and beta-carotene (mu mol/L), in different moments during pregnancy, on maternal hemoglobin (Hb, g/L) and anemia (Hb < 110.0 g/L) at delivery, and newborn BW (kg). Methods In a prospective cohort study in Cruzeiro do Sul, Western Brazilian Amazon, biomarkers of the VA status were assessed in the second and third trimesters in pregnancy. Serum retinol and beta-carotene were analyzed considering their effects in each and in both assessments (combined VA status), and the difference of serum values between assessments. Multiple linear and Poisson regression models were used with a hierarchical selection of covariates. Results A total of 488 mother-newborn pairs were surveyed. Combined VA deficiency status increased the risk for maternal anemia (adjusted prevalence ratio: 1.39; 95% CI 1.05-1.84), and was negatively associated with maternal Hb (beta - 3.30 g/L; 95% CI - 6.4, - 0.20) and newborn BW (beta - 0.10 kg; 95% CI - 0.20, - 0.00), adjusted for socioeconomic, environmental, obstetric, and antenatal characteristics, and nutritional indicators. However, the association for newborn BW was no longer significant after further adjustment for plasma ferritin. There were no significant associations between serum beta-carotene and the outcomes studied. Conclusion Poor serum retinol status throughout pregnancy was associated with maternal anemia at delivery in Amazonian women. The current World Health Organization protocols for supplementation during antenatal care should consider VA status for planning recommendations in different scenarios.