VITAMIN D supplementation during pregnancy may be linked to a lower risk of certain adverse maternal and neonatal outcomes, a 2026 umbrella meta-analysis has found.
It could also reportedly improve anthropometric measurements.
Vitamin D Deficiency During Pregnancy
As pregnancy develops, so does the need for vitamin D, which can lead to a deterioration of an existing deficiency.
Emerging research spotlights the influence of vitamin D on various prenatal processes including immune function, metabolism, inflammation, and vascular health.
In fact, deficiency during pregnancy has emerged as a significant public health concern.
Its prevalence ranges from 9% to 94%, dependant on country, race, ethnicity, skin colour, clothing customs, and dietary intake.
Vitamin D Lowered Risk of Adverse Maternal and Neonatal Outcomes
Researchers collected data from more than 188,000 participants.
Prenatal vitamin D supplementation lowered the risk of: gestational diabetes, preeclampsia, preterm delivery, low birth weight, the neonate being small for gestational age, stillbirth, and neonatal mortality.
Simultaneously, it enhanced: birth weight, birth length, and head circumference.
Results remained consistent across lower doses of vitamin D, shorter intervention periods, and among older participants.
In some subgroups, supplementation was also linked to a reduced risk of caesarean deliveries.
Clinical Implications for Prenatal Care
Whilst researchers acknowledged the value of vitamin D supplementation as an important component of prenatal care following the research findings, they also warned that this does not equate to a definitive prevention of all adverse events.
Nonetheless, authors called for the exploration of optimal and safe dosages, supplementation protocols, the appropriate time to start the intervention around pregnancy, and the effects of vitamin D when taken alongside other supplements.
References
Lin L et al. Vitamin D supplementation during pregnancy and maternal and neonatal outcomes: results from a quantitative umbrella meta-analysis. BMC Pregnancy Childbirth. 2026;DOI:10.1186/s12884-026-08994-6.
Fogacci S et al. Vitamin D supplementation and incident preeclampsia: a systematic review and meta-analysis of randomized clinical trials. Clin Nutr. 2020;39(6):1742-1752.
Zabul P et al. A proposed molecular mechanism of high-dose vitamin D3 supplementation in prevention and treatment of preeclampsia. Int J Mol Sci. 2015;16(6):13043-13064.
Irwinda R et al. Vitamin D supplementation higher than 2000 IU/day compared to lower dose on maternal-fetal outcome: Systematic review and meta-analysis. J Women’s Health. 2022;DOI:10.1177/17455057221111066.
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