Research is continuing to support the importance of maintaining healthy vitamin D levels during pregnancy and breastfeeding. In fact, low maternal vitamin D status has been linked with a variety of health outcomes, including preterm birth, preeclampsia, rickets and low birth weight. Yet, vitamin D deficiency continues to plague pregnant women and infants throughout the world.
Past research has shown that prenatal 25(OH)D levels are closely related to that of her child’s umbilical cord level. However, researchers recently hypothesized that particular subgroups may have a greater variation between maternal and neonatal vitamin D status, and thus may require an individualized approach to treating deficiency.
The researchers gathered 241 women in their 3rd trimester of pregnancy, as part of an NIH and institutionally funded cohort study. The participants filled out a health survey and serum 25(OH)D levels were obtained during enrollment into the study. Upon delivery, the researchers gathered the infants 25(OH)D status through the cord blood.
The researchers discovered the following:
- Overall, the prenatal and cord 25(OH)D levels were highly correlated (r = 0.75).
- The average infant cord blood level was around half of that of their mothers (10.9 ng/ml and 23.6 ng/ml, respectfully).
- The primary factors that affected the infant’s vitamin D status included maternal race, birth order and maternal vitamin D status.
- A total of 68.8% of infants had 25(OH)D levels <50% of their mothers, while 15.4% of infants had <25% of their mothers 25(OH)D levels.
- When maternal 25(OH)D levels reached <15 ng/ml, there was no longer any significant association with their infants’ vitamin D status, indicating a threshold effect may exist (r = 0.16; p = 0.22).
- Infants were likely to receive only 25% of their mothers vitamin D status if their mothers were vitamin D deficient (p = 0.003) and if the infant was born during the winter months (p = 0.05).
The researchers concluded,
“These data suggest mothers may reduce their contribution to the fetus’s 25(OH)D supply once their own level becomes low.”
In order to further validate these findings, clinical trials are needed. The Vitamin D Council recommends pregnant and breastfeeding women supplement with 5,000 IU vitamin D3 daily in order to prevent vitamin D deficiency among both mothers and infants as well as promote a successful pregnancy and birth.
Sturges, M. & Cannell, JJ. Study evaluates the relationship between maternal and offspring vitamin D status. The Vitamin D Council Blog & Newsletter. 2017.