Can I take vitamin D while pregnant?

Can I take vitamin D while pregnant?

Yes, and you probably should. Vitamin D plays a crucial role in pregnancy, supporting calcium absorption, immune function, and fetal bone development. Many people are deficient in vitamin D, particularly those who live in northern latitudes, have darker skin, or spend limited time outdoors.

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What the research shows

A 2024 systematic review found that vitamin D supplementation during pregnancy may reduce the risk of preeclampsia and preterm birth. Another systematic review found that vitamin D supplementation increases both maternal and infant 25(OH)D levels and that it may reduce maternal insulin resistance.

How much vitamin D do you need?

The official RDA during pregnancy is 600 IU per day, but many experts and recent studies suggest this is too conservative. American College of Obstetricians and Gynecologists (ACOG) and the Endocrine Society have both supported higher intakes, and doses of 1000-4000 IU per day are commonly recommended in clinical practice, particularly for people who are deficient.

Studies indicate that maternal vitamin D supplementation of 4000 IU per day effectively supports both maternal and infant vitamin D status. If you're unsure where you stand, ask your provider to check your 25(OH)D level through a simple blood test.

Vitamin D3 vs. D2

Vitamin D3 (cholecalciferol) is the preferred form because it's more effective at raising and maintaining blood levels than vitamin D2 (ergocalciferol). Most quality prenatal vitamins use D3. The source matters too: the most studied source is lanolin-derived D3, which has a long track record of safety and effectiveness.

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A note from WeNatal on vitamin D during pregnancy

WeNatal for Her includes 4000 IU of vitamin D3, which is one of the highest levels among prenatal supplements on the market. Many prenatals contain only 400-600 IU, which may fall short if you're starting from a deficit. Vitamin D supplementation helps reduce the risk of miscarriage, preeclampsia, infection, gestational diabetes, low birth weight, preterm birth, and postpartum depression. If you're concerned about your vitamin D status, talk to your provider about testing.

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References

DePender S, Russell MM, DeJager J, Comstock SS. Impact of Maternal Vitamin D Supplementation during Breastfeeding on Infant Serum Vitamin D Levels: A Narrative Review of the Recent Evidence. Children (Basel). 2022;9(12):1863. Published 2022 Nov 30. doi:10.3390/children9121863

Gallo S, et al. (2020). Vitamin D supplementation during pregnancy. Journal of the Academy of Nutrition and Dietetics, 120(5):898-924. DOI: 10.1016/j.jand.2019.07.002

Moghib K, et al. (2024). Efficacy of vitamin D supplementation on the incidence of preeclampsia: a systemic review and meta-analysis. BMC Pregnancy and Childbirth, 24:852. DOI: 10.1186/s12884-024-07081-y