Alison Gernand, Penn State University – Vitamin D Matters During the First Trimester of Pregnancy

What role does vitamin D play in pregnancy?

Alison Gernand, associate professor of nutritional sciences at Penn State University, shows us the importance.

Alison Gernand is an Assistant Professor of Nutritional Sciences at Penn State University. The focus of her research is the impact of maternal micronutrient status on adverse pregnancy outcomes. She received a master’s degree in public health from the University of Texas School of Public Health and a PhD in human nutrition and international health from the Johns Hopkins Bloomberg School of Public Health. She is also a Registered Dietitian with extensive experience in public health nutrition. She is a member of the Center for Reproductive Biology and Health and the Center for Women’s Health Research at Penn State.

Vitamin D Matters During the First Trimester of Pregnancy

Low vitamin D status during pregnancy is common in the United States. Most prior research has focused on maternal vitamin D status in mid- to late-pregnancy in relation to health outcomes, and less is known about early pregnancy vitamin D status.

Our research examined first and second trimester maternal vitamin D in relation to growth of the fetus throughout pregnancy, and also in relation to risk for preterm birth. To do this, we measured vitamin D levels from blood samples that were collected for 351 women, who were part of a large study conducted at multiple sites in the United States between 2010-2013. We used ultrasound and birth measurements to compare fetal growth patterns and risk of preterm birth by vitamin D status.

We found that babies were longer who were born to women with high versus low first trimester vitamin D status. We also found that women with low status in the first trimester had over 4 times the risk of giving birth early compared to women with high vitamin D status. We found weaker associations between second trimester vitamin D and outcomes, suggesting that early pregnancy may represent a more critical time point for intervention for women who are vitamin D deficient. However, this is a single observational study with a relatively small number of preterm births, and these relationships should be tested in additional, larger studies.

Testing for vitamin D status is not currently part of standard prenatal care in the US. Clinical care providers should consider talking to pregnant patients about vitamin D at the first prenatal visit. We hope that our research can promote awareness of the importance of vitamin D to help improve health outcomes for both the mother and baby.