The most important vitamins and minerals during pregnancy are folic acid, iron, iodine, vitamin D, calcium, and choline. A good prenatal vitamin covers most of these, but understanding what each one does and how much you need helps you choose the right supplement and fill any gaps through food.
Ideally, you’ll start taking a prenatal vitamin before you conceive. The Mayo Clinic recommends beginning at least three months before pregnancy, since the most critical development happens in the earliest weeks, often before you know you’re pregnant. If you’re already pregnant and haven’t started, beginning now still provides meaningful benefits.
Folic Acid: The Most Time-Sensitive Nutrient
Folic acid helps the neural tube, the structure that becomes your baby’s brain and spine, form correctly in the first few weeks of pregnancy. This is why timing matters so much: the neural tube closes around 28 days after conception, which is roughly when most people first get a positive test. If you’re not already getting enough folic acid by then, you’ve missed the most critical window.
The CDC recommends 400 mcg of folic acid daily for all women who could become pregnant. Once you are pregnant, the recommended intake rises to 600 mcg per day. If you’ve had a previous pregnancy affected by a neural tube defect, the recommendation jumps to 4,000 mcg daily, which requires a separate prescription-strength supplement.
Most prenatal vitamins contain at least 400 to 800 mcg, so check your label. You’ll also get folate naturally from leafy greens, beans, citrus fruits, and fortified grains.
Iron: Supporting a Much Larger Blood Supply
Your blood volume expands by roughly 35% during pregnancy. On top of that, you’re building a placenta and growing a baby who needs iron for their own developing blood cells. These demands together triple your iron needs in the second and third trimesters.
The recommended daily intake during pregnancy is 27 mg. A low-dose supplement of around 30 mg per day, typically included in prenatal vitamins, is effective at preventing iron-deficiency anemia without the stomach upset that higher doses can cause. Studies have found that 30 mg works just as well as 60 or 120 mg regimens for keeping anemia at bay.
Iron is easier to absorb when taken with vitamin C (a glass of orange juice, for instance) and harder to absorb alongside calcium or coffee. If your prenatal vitamin upsets your stomach, taking it with food or before bed can help. Some people tolerate a different form of iron better, so switching brands is worth trying before giving up on supplementation.
Iodine: Protecting Thyroid Function
Your body needs more iodine during pregnancy because your thyroid ramps up hormone production, your kidneys excrete more iodine than usual, and your baby’s developing thyroid needs its own supply. The recommended intake is 220 mcg per day.
Severe iodine deficiency during pregnancy can cause hypothyroidism in both mother and baby, and it’s linked to impaired cognitive development and congenital abnormalities. Most people in the U.S. get iodine through iodized salt, dairy products, and seafood, but not all prenatal vitamins include it. Check the label for iodine, because roughly half of the prenatal vitamins on the market leave it out.
Vitamin D: Building Your Baby’s Skeleton
Vitamin D helps your body absorb calcium, which is essential for building your baby’s bones and teeth. The recommended intake during pregnancy is 600 IU (15 mcg) per day, the same as for non-pregnant adults.
Many people are already low in vitamin D, especially those who live in northern climates, have darker skin, or spend limited time outdoors. Most prenatal vitamins contain 400 to 600 IU. If your blood levels are low, your provider may suggest a higher dose, but the standard prenatal amount is sufficient for most people.
Calcium: Bone Health and Blood Pressure
You need about 1,000 mg of calcium daily during pregnancy, which is actually the same as before pregnancy. The difference is that if you don’t get enough, your baby will pull calcium from your bones. Over time, that can weaken your skeleton.
Most prenatal vitamins contain only 100 to 300 mg of calcium because it’s a bulky mineral that would make pills enormous. That means food sources matter: a glass of milk or a cup of yogurt delivers roughly 300 mg each. Fortified plant milks, cheese, tofu made with calcium sulfate, and canned sardines with bones are other reliable sources.
For women with low dietary calcium intake, the World Health Organization recommends 1.5 to 2 grams of supplemental calcium per day to reduce the risk of preeclampsia, a dangerous pregnancy complication involving high blood pressure. If your diet is already calcium-rich, this level of supplementation likely isn’t necessary.
Choline: An Often Overlooked Nutrient
Choline plays a direct role in fetal brain development, yet most prenatal vitamins contain little or none of it. The current adequate intake for pregnant women is 450 mg per day, a number set back in 1998 based on liver function in men, not on outcomes in babies.
Research from Cornell University suggests that higher choline intake during pregnancy produces lasting cognitive benefits. In one study, children whose mothers consumed 930 mg per day during pregnancy maintained better sustained attention at age 7 compared to children whose mothers took 480 mg per day. Earlier testing of the same children showed faster information processing speed throughout the first year of life.
Eggs are the single best food source of choline, with one large egg providing about 150 mg. Beef liver, chicken, fish, and soybeans are also good sources. Since most prenatal vitamins fall short on choline, paying attention to food intake is particularly important for this nutrient.
DHA Omega-3: Brain and Eye Development
DHA, a type of omega-3 fat, is a structural component of your baby’s brain and retinal tissue. It accumulates rapidly in the fetal brain during the third trimester. Most experts recommend at least 200 to 300 mg of DHA per day during pregnancy.
Some prenatal vitamins include DHA, often as a separate softgel. If yours doesn’t, eating two servings of low-mercury fish per week (salmon, sardines, herring, or trout) will get you there. Fish oil supplements are another option if you don’t eat seafood.
What a Good Prenatal Vitamin Covers
No single pill contains everything in ideal amounts. A well-formulated prenatal vitamin should include at least folic acid (400 to 800 mcg), iron (27 to 30 mg), iodine (150 to 220 mcg), vitamin D (600 IU), and some DHA. Many will also include vitamin C, vitamin B6 (which can help with nausea), vitamin B12, and zinc.
Where prenatal vitamins consistently fall short is calcium and choline. These nutrients require larger physical amounts that don’t fit neatly into a single daily pill. Plan to get the bulk of your calcium and choline from food, or add a separate supplement if your diet doesn’t cover it.
Practical Tips for Taking Prenatals
Nausea is the most common reason people stop taking their prenatal vitamin, especially in the first trimester. If swallowing a large pill triggers your gag reflex, gummy prenatals are gentler on the stomach, though they typically skip iron and may contain less of other nutrients. Taking your vitamin at night or with a small snack can also reduce queasiness.
If you can’t keep any prenatal down during severe morning sickness, the priority nutrient to take separately is folic acid. It comes in small, easy-to-swallow tablets and covers the most time-sensitive need. You can add the full prenatal back in once nausea eases, usually around weeks 12 to 14.
Store brands and name brands use the same active ingredients and are held to the same manufacturing standards. Price doesn’t determine quality. What matters is the label: compare it against the key nutrients listed above and choose the one that covers the most ground in a form you’ll actually take every day.