Maternal Vitamin D Supplementation and Infantile Rickets: Secondary Analysis of a Randomized Trial

Area of Science:

• Nutritional science
• Maternal and infant health
• Public health in low- and middle-income countries

Background:

• The efficacy of maternal vitamin D supplementation for preventing infantile rickets is not well-established, especially in regions without routine infant supplementation.
• This study investigates dose-ranging effects of maternal vitamin D on rickets risk in Bangladesh.

Purpose of the Study:

• To evaluate the impact of different doses of maternal vitamin D supplementation on the incidence of biochemical rickets in infants.
• To determine the optimal timing and duration of vitamin D supplementation for preventing rickets.

Main Methods:

• A randomized, placebo-controlled trial involving 1300 pregnant women was conducted.
• Participants received varying weekly doses of vitamin D (4200, 16,800, or 28,000 IU) or placebo, with different supplementation schedules (prenatal, postpartum, or combined).
• Infants (n=790) were screened for biochemical rickets between 6 and 12 months of age.

Main Results:

• Biochemical rickets was diagnosed in 4.9% of infants overall, with the highest prevalence in the placebo group (7.8%).
• Maternal supplementation with 28,000 IU/week of vitamin D, both prenatally and postpartum, significantly reduced rickets risk (1.3%; RR, 0.16; 95% CI, 0.03-0.72).
• Prenatal-only supplementation at various doses did not show a significant reduction in rickets risk compared to placebo.

Conclusions:

• Maternal vitamin D supplementation, particularly 28,000 IU/week from the third trimester through 6 months postpartum, effectively lowers the risk of infantile biochemical rickets.
• Further research is necessary to establish optimal postpartum vitamin D dosage recommendations for lactating mothers.