Antenatal Oral Vitamin D Supplementation and Serum 25(OH)D Concentration in Exclusively Breastfed Infants

A recent study aimed to compare the proportion of exclusively breastfed (EBF) infants with severe vitamin D deficiency—defined as serum 25(OH)D concentration <11 ng/mL—at 6 months of age, following maternal supplementation with 300,000 IU of vitamin D₃ or placebo during the third trimester of pregnancy.

This randomized, double-blind, placebo-controlled trial included 100 pregnant women at 30–32 weeks of gestation who intended to exclusively breastfeed for 6 months. Participants were randomized to receive either 60,000 IU of oral vitamin D₃ or a placebo weekly for 5 weeks during the third trimester. Serum 25(OH)D, calcium, phosphorus, and alkaline phosphatase levels were measured at baseline (enrollment), in cord blood at delivery, and in infants at 6 months of age. The primary outcome was the proportion of infants with severe vitamin D deficiency and the incidence of rickets at 6 months.

A total of 72 mother–infant pairs were followed until 6 months postpartum. At enrollment, the mean maternal serum 25(OH)D concentrations were comparable between the two groups. However, the mean 25(OH)D concentration in cord blood was significantly higher in the intervention group than in the control group. By 6 months of age, infants in the intervention group had higher serum 25(OH)D levels compared to those in the control group. Notably, none of the infants in the intervention group developed severe vitamin D deficiency, whereas 54.3% of infants in the control group were deficient. Furthermore, no cases of rickets were observed in the intervention group.

 Third-trimester maternal supplementation with vitamin D₃ effectively prevents severe vitamin D deficiency in exclusively breastfed infants at 6 months of age. This strategy may reduce the long-term risk of respiratory, metabolic, and neurological disorders in these children. In addition to benefiting infants, maternal supplementation also helps correct vitamin D deficiency in mothers. However, it remains important to monitor for potential hypervitaminosis.

Source: Prabhakar P, Faridi MM, Aggarwal A, et al. Indian Pediatrics. 2024 Jun;61(6):533-9.

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