Pregnant women who don't get enough vitamin D have a high risk of delivering babies with lower birth weight, says a new study.
"A mother's vitamin D level early in pregnancy may impact the growth of her baby later in pregnancy. Also, if the mother was deficient in vitamin D during the first trimester, her baby had twice the risk of suffering from growth restriction in utero," said Alison Gernand, from Pitt Public Health's Department of Epidemiology and lead author of the study.
The study included 2,146 pregnant women enrolled in the Collaborative Perinatal Project which was conducted in 12 medical centers across the U.S. from 1959 to 1965. The blood samples of participants were preserved and were tested for vitamin D levels.
Study results showed that women who had low levels of vitamin D during the 26 weeks of pregnancy delivered babies who weighed 46 grams less than their peers.
Low birth weight puts children at higher risk of death in their first month. These children also suffer from high risk of chronic diseases, like heart disease, hypertension and type-2 diabetes.
Babies born small for gestational age are at five to 10 times greater risk for death in their first month and have a higher risk of chronic diseases, such as heart disease, hypertension and type 2 diabetes, later in life.
"This is one of the largest studies to examine a mother's vitamin D levels and their relationship with birth weights. It shows that clinical trials to determine if you can improve birth weights by giving women of reproductive age vitamin D supplements may be warranted," said Lisa M. Bodnar, from Pitt Public Health's Department of Epidemiology and senior author of the study.
Researchers say that the study results would probably differ in modern-day samples as women today weigh more, smoke less and get more vitamin D from food than from sun exposure, which might have an impact on their vitamin D levels and their babies' birth weight.
Interestingly, previous research has suggested that pregnant women who don't get enough vitamin D are more likely to have obese children.
The study is published in Journal of Clinical Endocrinology & Metabolism.