The ultimate guide to prenatal multivitamins when trying to conceive

The million-dollar question in fertility conversations: what is the best prenatal multivitamin? The industry is confusing, to say the least, with countless products and often conflicting claims. And if you’re trying to conceive, you need slightly different ingredients and amounts than someone who is already pregnant. No wonder most people feel lost and overwhelmed.

We created a science-backed process for evaluating prenatal multivitamins when trying to conceive, and we’ll walk you through it. Before we dive in, the most important point: the best prenatal for you is one you will take consistently. Even the best formula won’t help if you don’t take it, so always weigh your budget, lifestyle, and preferences.

We don’t make supplements, so this guide is based purely on the latest fertility science, with no marketing language.

What are the most important nutrients in a prenatal?

Most prenatals are formulated around estimated nutrient needs during pregnancy. When we evaluate them through the lens of trying to conceive, we care about two things:

• Nutrients that support a healthy pregnancy. We want your body to enter pregnancy with sufficient stores of the nutrients that help your baby grow and develop.
• Nutrients that can affect fertility or egg quality. Your reproductive system needs certain nutrients. It’s great to get them from your diet; your prenatal acts as a backup against critical gaps that could limit your fertility potential.

To identify them, we start with the nationally established Recommended Dietary Allowances (RDAs), then dig into the research to see whether any nutrient should be included in higher amounts. Population-based recommendations take time to catch up with research, so we don’t simply accept the status quo. Nine nutrients matter most when picking a prenatal: folate, vitamin B12, vitamin B6, choline, vitamin D, vitamin A, iodine, iron, and DHA.

How much of each nutrient should your prenatal have?

Below are the best-case amounts we recommend based on the latest fertility research. It’s hard to find a prenatal that meets them perfectly, so we’ve also listed a minimum: make sure your prenatal contains at least that much.

* We’re always watching for new or reformulated products, and for new research.
** DFE stands for Dietary Folate Equivalent, a unit that accounts for how differently the body absorbs each form of folate (for example, folic acid versus methylfolate). It lets you focus on the amount your body gets rather than the form.

Folate

Folate is crucial in early conception to prevent neural tube defects, which is why public health messaging strongly encourages folic acid for anyone who could become pregnant. The US Preventive Services Task Force Opens in a new tab: recommends a supplement containing 400 to 800 mcg of folic acid, in line with other major medical bodies.

Folic acid is the only form of folate shown in randomized controlled trials and food-fortification programs to prevent neural tube defects. Other forms, including 5-MTHF (methylfolate), haven’t been studied for this, though in theory they should also be effective.

While 400 to 800 mcg reduces the risk of neural tube defects, it is at the lower end of what some studies associate with supporting fertility (Opens in a new tab: 1, Opens in a new tab: 2, Opens in a new tab: 3). That’s why we recommend at least 800 mcg of folic acid, which equals 1,330 mcg DFE on a supplement label.

Vitamin B12

In early conception, vitamin B12 works alongside other B vitamins and choline to support Opens in a new tab: brain and spinal cord development. Among people undergoing assisted reproduction, adequate B12 status may be associated with better Opens in a new tab: embryo quality, Opens in a new tab: improved embryonic growth, and even higher chances of Opens in a new tab: clinical pregnancy and Opens in a new tab: live birth.

Research suggests intakes above the RDA are likely needed to support B12 status (Opens in a new tab: 1, Opens in a new tab: 2). B12 is well tolerated at high doses and has no established upper limit, so we recommend at least 10 mcg.

Vitamin B6

Vitamin B6 is involved in amino acid metabolism, red blood cell formation, and a developing baby’s brain and spinal cord. Accurate data are hard to come by, because it’s unclear how B6 biomarker levels relate to Opens in a new tab: clinical outcomes. We do know that supplements are a crucial source of B6 (Opens in a new tab: 1, Opens in a new tab: 2) and can greatly reduce deficiency, though typical multivitamin doses may be too low to prevent a drop in Opens in a new tab: B6 levels in late pregnancy. For now, we recommend at least 5 mg.

Choline

Choline, along with the B vitamins, helps Opens in a new tab: prevent neural tube defects. During pregnancy it is critical for your baby’s brain and spinal cord development, and may be linked to long-term cognitive function (Opens in a new tab: 1, Opens in a new tab: 2).

We’d love to see at least 450 mg in prenatals, but choline is bulky, and that isn’t yet feasible for many products. The next best option is at least 150 mg. Typical dietary intake among women of reproductive age is about 300 mg a day (only Opens in a new tab: 4% of people meet the recommended intake), so an extra 150 mg brings you to the 450 mg we’re aiming for.

Vitamin D

Much research has sought causal links between vitamin D and reproductive outcomes, with few clear conclusions. What we do know is that vitamin D is involved in many crucial processes, including reproduction, and that deficiency can harm fertility potential. Because Opens in a new tab: deficiency and insufficiency are common in the US and Opens in a new tab: typical intake is low, we recommend at least 20 mcg (800 IU). If you live in a colder climate, have darker skin, or spend little time outdoors, 50 mcg (2,000 IU) is likely a better choice.

Vitamin A

Vitamin A is involved in egg production, cell division, embryo formation, early fetal development, and placental function (Opens in a new tab: 1, Opens in a new tab: 2). Harmful deficiency is rare in the US, but about Opens in a new tab: half of women of childbearing age get less than recommended. The RDA for vitamin A isn’t derived from solid data, so for now we recommend at least 1,200 mcg.

Ideally, look for a source of preformed vitamin A (retinol or retinyl esters), which is the most bioavailable. Carotenoids are still a useful source, but Opens in a new tab: absorption varies widely between individuals. Because vitamin A is fat-soluble and stored in the body, supplements should not contain more than 3,000 mcg of preformed vitamin A (this limit doesn’t apply to carotenoids).

Iodine

Iodine is crucial in pregnancy because of its role in thyroid function and fetal brain development, and early research suggests low intake before conception may be linked to reduced fertility (Opens in a new tab: 1, Opens in a new tab: 2). Severe deficiency is rare in North America, but Opens in a new tab: recent research has found rising rates of subclinical deficiency, likely due to lower salt and dairy intake, the switch to non-iodized salts at home, and processed foods that don’t use iodized salt. We recommend 220 mcg.

Iron

Iron is crucial in pregnancy to prevent maternal anemia. Research hasn’t consistently linked iron to fertility, but we want you to enter pregnancy with adequate stores. Needs are highly individual and depend on diet and genetics, so we recommend the full non-pregnant RDA of 18 mg.

If your iron levels are adequate and your diet is rich in iron (regular red meat, poultry and fish), a product with less or no iron may suit you. If you eat a plant-based diet or know your levels are low, a higher dose is more appropriate; many products are designed for pregnancy, when needs rise to 27 mg a day. If you already take an iron supplement, ask your doctor which dose is right for you. Iron can also cause constipation: if it does, ask your doctor to test your levels. Needs rise sharply in the second trimester, so you may be able to avoid unnecessary discomfort before conception.

DHA

DHA, an omega-3 fatty acid, is associated with many positive outcomes, including a higher probability of natural Opens in a new tab: conception and, with assisted reproduction, better Opens in a new tab: embryo morphology and higher Opens in a new tab: clinical pregnancy and live birth rates. Like choline, it’s bulky. We like to see 200–500 mg in a prenatal, but even that is below the amounts linked to improved fertility, so we typically recommend a separate DHA supplement while trying to conceive.

Is more always better? A note on mega doses

Giant doses of certain vitamins have become a trend in prenatals. A few things to keep in mind:

• You can’t out-supplement a poor diet. A prenatal is an insurance policy, not the main event; look to your diet to close nutrient gaps.
• Mega doses are often of water-soluble vitamins such as B12 and B6. They are likely safe, but the body rapidly excretes the excess (in other words, expensive urine).
• Your physician should guide any decision about mega doses. In some cases a doctor will recommend very high doses of folic acid; in others, those doses could be harmful.
• Brands with mega doses often claim health benefits, but there is no robust research on them yet, and doses hundreds of times above estimated needs are unlikely to help.

If a supplement company makes a claim that sounds too good to be true, it probably is.

Capsules, powders or gummies?

The best format is the one you’ll take consistently. If capsules or tablets don’t work for you, a powder may be the way to go; if you thrive on routine, daily capsules or tablets with a meal may make more sense. With capsules and tablets, expect to take two to four a day for a high-quality product with the nutrients you need.

Our one caution is with gummies: it’s difficult to fit all the recommended nutrients into a gummy. If you struggle with capsules or tablets, look at powders before gummies.

Putting it together: picking a prenatal that’s right for you

If you already take a prenatal, compare its label against the “best case” and “we’ll take it” amounts above. If you’re choosing a new one, compare the brands you’re considering. Fancy branding and high prices aren’t always the best options: designer prenatals have driven prices up, but there are great options for under $40 a month. If a brand charges more than $70 a month, you’re likely paying for sleek marketing.