May 19, 2026

When should you take prenatal vitamins?

by Raegen Barger, RDN, LD, IFNCP

When should you take prenatal vitamins?

The ideal time to start is at least three months before you begin trying to conceive. Six months is even better. The neural tube closes within the first 28 days after conception, often before a missed period. Folate needs to be circulating in adequate amounts in your blood before that window closes.

The U.S. Preventive Services Task Force (USPSTF) recommends daily supplementation with folate for all women planning or capable of pregnancy. They classify this as a Grade A recommendation, meaning high certainty the benefits are substantial.

RELATED: How to choose a prenatal vitamin

Why starting early matters

Research on red blood cell folate concentrations shows that it takes approximately three to six months of consistent supplementation to reach the optimal threshold associated with the lowest risk of neural tube defects.

Beyond folate, many nutrients in prenatal vitamins (iron, vitamin D, choline, DHA) take time to accumulate in your tissues. Starting early means you're not playing catch-up once pregnancy begins. And since roughly half of pregnancies are unplanned, there's a strong case for anyone of reproductive age to be taking some form of folate daily.

What if you didn't start before conception?

Start now. Whenever you find out you're pregnant, begin taking a comprehensive prenatal vitamin immediately if you haven't already. While earlier is better for neural tube protection specifically, prenatal vitamins offer benefits throughout pregnancy. No guilt, no panic. The body is remarkably adaptable, and starting at any point is better than not taking them at all.

Don't forget about him

Sperm take approximately 70-90 days to fully develop. That means the quality of sperm at the point of conception reflects the nutrition and lifestyle from about three months prior. For couples trying to conceive, both partners starting their prenatals three to six months before is the optimal approach.

A note from WeNatal on when to start

WeNatal for Her was designed to be the prenatal you start before you conceive. With methylfolate, iron, choline, and vitamin D3 included at science-backed levels, it gives your body the time it needs to build real nutrient reserves. WeNatal for Him supports the male side of the equation with CoQ10, zinc, selenium, and methylfolate for optimal sperm health. Starting early is one of the simplest, most proactive steps a couple can take together.

References

Barry MJ, et al. (2023). Folic acid supplementation to prevent neural tube defects: USPSTF reaffirmation recommendation statement. JAMA, 330(5):454-459. DOI: 10.1001/jama.2023.12876

Viswanathan M, et al. (2023). Folic acid supplementation to prevent neural tube defects. JAMA, 330(5):460-466. DOI: 10.1001/jama.2023.9864

Raegen Barger, RDN, LD, IFNCP

Raegen, a registered dietitian and board-certified integrative and functional nutritionist, is passionate about supporting clients with personalized, research-based approaches to nutrition and wellness. She focuses on the generational impact of nutrition and lifestyle, helping clients improve lab markers, manage symptoms, achieve health goals, and build sustainable, balanced habits. A proud mom of two, Raegen is also a WeNatal Nutritionist.