LOS ANGELES—A new publication led by a Heluna Health researcher has found that low levels of vitamin D in the first trimester of pregnancy are associated with a higher risk of preterm birth and shorter gestational duration. Conducted using data from the large Monitoring Mothers-to-Be (nuMoM2b) cohort study, the research offers critical insights into how early pregnancy vitamin D levels influence fetal growth and birth outcomes.
“While it’s already well established that maternal health is critical to fetal development, our collaborative research team aimed in this study to better understand the role of vitamin D in fetal growth and pregnancy outcomes, in particular implications for timing of vitamin D supplementation,” said Celeste Beck, PhD, MPH, associate research scientist at Heluna Health and lead author of the study, which was published in December 2024 in the American Journal of Clinical Nutrition.
Researchers analyzed data from 351 pregnant individuals across eight study sites in the United States. Maternal vitamin D levels were measured from blood samples taken during the first and second trimesters of pregnancy. Fetal growth was measured by multiple ultrasounds throughout pregnancy, along with growth measures taken at birth. The multicenter study was led by researchers at Heluna Health and Penn State in collaboration with the University of Utah.
Individuals with first-trimester vitamin D levels below 40 nanomoles per liter (nmol/L) were 4.35 times more likely to deliver preterm compared to those with levels above 80 nmol/L. They also delivered an average of 1.17 weeks earlier.
Researchers observed a strong connection between first-trimester vitamin D levels and certain fetal growth patterns. Specifically, a 10 nmol/L increase in maternal vitamin D concentrations during the first trimester was associated with a modest but significant increase in fetal length. Vitamin D levels were not linked to fetal weight or head circumference growth.
“Our findings emphasize the importance of maternal health during early pregnancy,” Beck said.
Vitamin D is known to play a crucial role in skeletal development and immune function, which are vital during early pregnancy. Prior studies have shown that low vitamin D levels can impair placental development and increase inflammation, factors linked to adverse outcomes like preterm birth.
Findings from the current study align with growing evidence that early pregnancy, or even the preconception period, may be a critical window for optimizing maternal vitamin D levels, Beck said. Public health recommendations may need to emphasize timing, dosage and accessibility of vitamin D supplementation to reduce risks, particularly during winter months when sun exposure is limited.
“Future research should explore whether preconceptual vitamin D supplementation could further mitigate these risks and improve fetal development,” Beck said.
The study contributes to an ongoing conversation about the importance of nutrition and early prenatal care in improving maternal and infant health outcomes.
Jo Kay Ghosh, PhD, MPH, director of research and evaluation at Heluna Health, said this study strongly aligns with the larger context of ongoing work at Heluna Health.
“Heluna Health has long been an advocate for maternal health and nutrition,” Ghosh said. “This study arms us with more data to support our public and population health initiatives.”
About Heluna Health
For more than 50 years, Heluna Health has collaborated with community-based organizations, public health agencies, healthcare systems, providers, and policymakers to enhance public health interventions that support equitable access to disease prevention, treatment, care and social resources. Heluna Health is at the forefront of efforts to eliminate health disparities among vulnerable populations, dedicating itself to culturally congruent, community-led interventions aimed at systemic change and improved health outcomes.
Funding: This study was supported by funds from the U.S. Department of Health and Human Services, National Institutes of Health, and Eunice Kennedy Shriver National Institute of Child Health and Human Development (TL1TR002016, 1K12 HD085816, U10 HD063020, U10 HD063037, U10 HD063041, U10 HD063046, U10 HD063047, U10 HD063048, U10 HD063053, U10 HD063072). Funding sources had no publication involvement or restrictions.
Read more at Helunahealth.org: Maternal Health – The Answer is in the Community
