Endocrine Abstracts

This review assessed recent literature (RCTs, longitudinal studies, meta-analyses) from the past decade via PubMed, Google Scholar, and Scopus to gauge the impact of prenatal and postnatal vitamin D (VD) supplementation on maternal and infantile vitamin D status.

Results: We analyzed 12 studies (n=6253 mothers). In a prospective interventional study involving 80 women who received two doses of VD injections (600,000 IU/ml each), 60% of women displayed unsatisfactory VD levels despite high-dose treatment. A randomized study of 180 women at 27 weeks’ gestation explored different vitamin D supplementation strategies: a single oral dose of 200,000 IU VD, a daily supplement of 800 IU VD from 27 weeks until delivery, and a no-treatment group. Supplemented groups exhibited significantly higher 25-hydroxyvitamin D (25OHD) levels and lower secondary hyperparathyroidism instances. Cord blood 25OHD levels significantly increased with maternal supplementation. Maternal supplementation during lactation elevated infant serum 25OHD levels, with higher doses proving more effective in boosting infantile 25OHD. Maternal supplementation with 50 μg VD₃/d during gestation safeguarded 98% of unsupplemented breastfed infants from VDD (<30 nmol/l) for at least 8 weeks. In comparison, 10 or 25 μg VD/d protected only 57% and 84% of infants, respectively. Maternal VD supplementation dosages displayed nonlinear effects on maternal and infantile 25OHD concentrations. High doses (≥6000 IU/day) effectively rectified VDD in both mothers and infants. A maternal dose of 6400 IU/day surpassed the 400 and 2,400 IU doses in achieving VD sufficiency. A longitudinal study involving 6-month maternal supplementation with 6000 IU resulted in 96% of mothers attaining adequate serum 25(OH)D levels (≥50 nmol/l), compared to 52% for those on 600 IU (P<0.0001). Infants born to mothers on 600 IU, supplemented with 400 IU vitamin D3, displayed slightly higher serum 25OHD levels compared to those born to mothers on 6000 IU alone. Among Arab women randomized at 12-16 weeks’ gestation, supplementation with 400, 2000, and 4000 IU/d VD3 demonstrated that higher maternal doses were more effective in increasing maternal and infant 25OHD levels. In another study, maternal supplementation with 4000 IU of vitamin D during lactation resulted in adequate serum vitamin D levels in >90% of infants.

Conclusion: For breast-fed infants, a recommended dose is 400 IU vitamin D3/day. Alternatively, maternal supplementation with 4000 to 6,400 IU vitamin D3/day during pregnancy and lactation can augment breast milk’s vitamin D content, offering a practical choice.