What do prenatal vitamins do for a woman?
Prenatal vitamins help ensure a woman has adequate nutrients to support both herself and her developing baby during this demanding time. When a pregnant woman is nutrient deficient, her body will prioritize the baby's needs first—often at her own expense. Research demonstrates that maternal calcium stores are mobilized from bone to meet fetal demands when dietary intake is insufficient, potentially compromising the mother's bone health.² This same principle applies to other nutrients: the mother will deplete her own reserves to support fetal development.
This is why so many pregnant women experience fatigue, brain fog (often called "mommy brain"), and even gallbladder issues—choline deficiency is associated with impaired gallbladder function and bile production.³ Folate is critical for proper closure of the neural tube, which forms the baby's brain and spine within the first 28 days after conception—often before a woman knows she's pregnant.⁴ This is why health organizations recommend beginning supplementation before conception.
Is it good to take prenatals when not pregnant?
Yes—particularly if you're planning to conceive or are of childbearing age. Because neural tube development occurs so early in pregnancy, the USPSTF recommends folate supplementation for anyone who could become pregnant.¹ Starting a prenatal vitamin before conception helps build nutrient stores and ensures adequate folate levels during the critical early weeks.
Importantly, the quality of a woman's eggs depends significantly on her nutritional status. Research shows that oocyte maturation takes approximately 90 days, and nutritional interventions during this window can influence egg quality and subsequent pregnancy outcomes.⁹ Preconception supplementation with multiple micronutrients has been shown to have beneficial effects on fertility, including increasing the chance of becoming pregnant and decreasing time to conception.¹⁰ By supplementing for at least three months prior to conception, a woman is actively supporting the health of her eggs—which directly impacts the health of her developing baby.
Even for women not actively trying to conceive, prenatal vitamins can support overall health through their B vitamins, trace minerals, and other nutrients that benefit energy levels, hair, skin, and nail health.
Which prenatal vitamin is best?
The best prenatal vitamin depends on your individual nutritional needs, health history, and tolerance:
If you have fertility concerns, past pregnancy complications, or are more nutrient deficient, choose Optimal Prenatal. This comprehensive formula includes antioxidants, choline, inositol, and betaine for broad-spectrum methylation support and addresses the higher nutritional demands of more challenging pregnancies.
If you're overall healthy, eating well, and have no history of pregnancy complications, Prenatal Essentials provides excellent foundational support without the added complexity.
If you cannot tolerate swallowing capsules, Prenatal Essentials Chewable offers the same quality nutrition in a more accessible format.
If you're sensitive to methyl donors—experiencing headaches, anxiety, or irritability from methylated nutrients—choose Optimal Prenatal Methyl-Free or Prenatal Essentials Methyl-Free. These use 100% folinic acid and hydroxocobalamin instead of methylfolate and methylcobalamin, providing folate support without overstimulating methylation.
When evaluating any prenatal, look for these key features:
Capsules, powders, or chewables—never tablets. Tablets are known to pass through the digestive system without fully dissolving, limiting nutrient absorption. Gummies are convenient but cannot deliver sufficient nutrient density for a healthy pregnancy—you simply cannot fit adequate amounts of key nutrients into a gummy format.
No folic acid. Synthetic folic acid can block natural active folates from binding to folate receptors, potentially interfering with folate transport to the developing baby's brain.¹¹ Look for methylfolate and folinic acid instead.
Real vitamin A, not just beta-carotene. Over 40% of women have a BCO1 gene variant that reduces their ability to convert beta-carotene into active vitamin A.¹² A prenatal containing only beta-carotene is a red flag—you want preformed vitamin A (retinyl palmitate) as well.
Folinic acid included. While methylfolate supports methylation, folinic acid supports healthy blood cell formation, immune function, and hair, skin, and nail health. Ideally, your prenatal includes both forms.
Vitamin D3 at 4,000 IU with vitamin K2 (MK-7) and magnesium. These three nutrients work synergistically to support bone health for both mother and developing baby. You need all three together for optimal benefit.¹³
What to avoid when taking prenatals?
Iron in your prenatal. We recommend keeping iron separate from your prenatal so you can tailor the amount to your specific needs. Iron is inflammatory at excessive levels, and taking too much creates problems.¹⁴ Iron also blocks calcium absorption when taken together—another reason to dose it separately.
Green tea around supplement time. Green tea contains compounds that block folate absorption.¹⁵ Enjoy it in moderation between meals.
Antacids. These suppress stomach acid, which is required for proper absorption of vitamin B12 and trace minerals. If you need antacid support, take it at a different time than your prenatal.
Fish oil with your prenatal. Take fish oil after dinner separately from your prenatal. Combining too much fat with nutrient-dense supplements can cause stomach upset. Taking fish oil in the evening also supports better tolerance.
What are potential side effects?
Side effects from prenatal vitamins are more likely to occur with methylated nutrients like methylfolate and methylcobalamin. Common symptoms include headaches, irritability, insomnia, and anxiety—signs that methylation may be overstimulated. If this happens, switch to a methyl-free prenatal.
Choline, if dosed too high, can contribute to low mood, fatigue, gas, and bloating due to excessive TMAO production. Using a prenatal that combines betaine, inositol, and choline—like Optimal Prenatal—provides a broad-spectrum approach to methylation support while minimizing side effects commonly associated with prenatals containing only methylfolate and high-dose choline.
If you're methyl-sensitive, use our MF (methyl-free) versions. If you need additional choline support or are using an MF prenatal, add Optimal PC after dinner. This provides phosphatidylcholine, which supports healthy brain and spinal development in babies, healthy cell membranes throughout the body, and liver function for mom.