What do prenatal vitamins do?

What do prenatal vitamins do?

Prenatal vitamins serve a specific purpose: they provide the additional vitamins and minerals that a pregnant body needs to support its own health and the development of a growing baby. Think of them as nutritional insurance. Even with a well-rounded diet, pregnancy increases nutrient demands to a point where food alone often falls short.

RELATED: The ultimate preconception guide: What to do when you’re ready to get pregnant 

Key nutrients and their roles

Folate is a headline nutrient. It supports the formation of the neural tube, which becomes the brain and spinal cord, during the first 28 days after conception. A 2024 systematic review found that folic acid supplementation reduced the risk of congenital anomalies by 77%.

Iron helps your body produce the extra blood it needs during pregnancy (blood volume increases by about 45%). It also supports oxygen delivery to the placenta and baby. Iron deficiency anemia during pregnancy is linked to preterm birth and low birth weight.

Vitamin D supports calcium absorption and fetal bone development. A 2024 Cochrane review found that vitamin D supplementation during pregnancy may reduce the risk of preeclampsia, though the overall evidence remains mixed due to study heterogeneity.

DHA (omega-3) plays a role in fetal brain and retina development, particularly during the third trimester when brain growth accelerates.

Choline supports neural tube development and placental function. Despite growing evidence for its importance, many prenatal vitamins still don't include it or provide it at levels below the recommended combined 450 mg per day through diet and supplementation.

Iodine is necessary for thyroid function, which regulates metabolism for both parent and baby.

Do they actually make a difference?

Yes. A 2022 review examining over 200 studies concluded that suboptimal vitamin intake from preconception through pregnancy is associated with a wide range of complications, including anemia, preeclampsia, gestational diabetes, preterm birth, low birth weight, and neural tube defects.

RELATED: How to choose a prenatal vitamin 

A note from WeNatal on what do prenatals do?

WeNatal for Her includes every one of these key nutrients at clinically meaningful doses: methylfolate, iron, vitamin D3, choline, and iodine, with Omega DHA+ providing optimal omega-3 fatty acids. They are designed not just to check boxes, but to deliver real nutritional support where the science says it matters most. Choosing a comprehensive, evidence-based prenatal is one of the most impactful things you can do for your pregnancy.

RELATED: Can men take prenatal vitamins? What to know about male prenatal nutrition

References

Adams JB, et al. (2022). Maternal Health, Neonatology and Perinatology, 8:4. DOI: 10.1186/s40748-022-00139-9

Moges N, et al. (2024). Frontiers in Pediatrics, 12:1386846. DOI: 10.3389/fped.2024.1386846

Palacios C, et al. (2024). Vitamin D supplementation for women during pregnancy. Cochrane Database of Systematic Reviews. DOI: 10.1002/14651858.CD008873.pub5