How to Choose the Best Prenatal Vitamins for You

Everything you need to know about picking a prenatal pill with the DHA, folic acid, and other vitamins to help you and baby thrive. 

pregnant woman taking prenatal vitamin wong sze yuen/ Shutterstock

If you're newly pregnant or trying to conceive, it's time to start paying serious attention to nutrition. For most women, that means taking a daily multivitamin. But with tons of over-the-counter and prescription options to choose from, how does an overwhelmed mom-to-be know what to take? Read on for our guide to choosing a good prenatal pill.

What to Look For in a Multivitamin

Prenatal vitamins often have a mile-long ingredient list that seems to include the whole alphabet of vitamins, but you should look for the right amounts of a few key nutrients, including: 

Folic Acid
Perhaps the most important ingredient in a prenatal vitamin is folic acid, a vitamin that can help prevent birth defects of the brain and spine (called neural tube defects). The March of Dimes recommends that all women of childbearing age get 400 micrograms of folic acid daily; increase that amount to 600 micrograms of folic acid daily once you become pregnant. Many prenatal vitamins include more, which is fine, says Julie Levitt, M.D., an ob-gyn at Women's Group of Northwestern in Chicago, because the folic acid found in supplements is more easily absorbed by our bodies than folate, the naturally occurring version. 

Iron
Prenatal vitamins with iron should be a top priority. You'll need twice as much of this mineral, now that you're pregnant, to make extra blood to take care of your baby. Pregnant women should get 27 milligrams of iron each day.

Calcium
This mineral is vital for the development of your baby's bones, teeth, heart, muscles, and nerves, and mamas-to-be should get 1,000 milligrams daily. Getting enough calcium should be a priority: Skimping now could increase your risk of osteoporosis later in life. "What the fetus doesn't get through the diet, the fetus will take out of mom's bones," says Scott Sullivan, M.D., the director of maternal-fetal medicine at Medical University of South Carolina. "A supplement protects mom from being the calcium reservoir."

Vitamin D
This vitamin helps you absorb calcium and is important for your baby's bones, teeth, eyes, and skin. March of Dimes suggests getting 600 IU (international units) of vitamin D a day during pregnancy, and many doctors recommend even more—800 or 1,000 IU—because many people are deficient.

Iodine
During pregnancy you need 220 micrograms of iodine every day to help your baby's brain and nervous system, according to March of Dimes. Dr. Sullivan recommends your prenatal pill have at least 150 micrograms (foods like fish and dairy can make up the rest) and says the source should be potassium iodide, as iodine from kelp can break down before you get a chance to take it.

How Many Supplements Do I Actually Need?

A prenatal vitamin will often contain 100 percent of the recommended daily allowance (RDA) for folic acid, and 100 percent or more of the RDA for iron, but it may have only around 250 mg of calcium, so if you don't get much in your diet (if you're vegan, for instance, or lactose intolerant) consider taking an additional supplement. You'll want to down it at a different time of day than your prenatal vitamin, as large amounts of calcium can't be absorbed along with the iron in your prenatal vitamin, says Dr. Levitt. You could take your iron supplement in the morning and your calcium supplement at night.

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Is It OK If Most of My Nutrition Comes from Prenatal Vitamins?

Prenatal vitamins provide a good nutritional foundation (especially for those early days or weeks when all you can stomach is crackers) but getting your nutrients from food is generally the best route. "A vitamin pill is no substitute for a healthy diet," says Laura Riley, M.D., a maternal-fetal specialist at Mass General Hospital in Boston. "If your typical lunch before you got pregnant consisted of a candy bar and a low-calorie soda, it's time to give your diet a makeover."

Foods contain other compounds your body needs, such as fiber, and calories your rapidly developing fetus needs that supplements don't provide. Aim to eat a diet rich in fruits, vegetables, non-fat dairy foods, whole grains, lean meats, and safe fish. Experts recommend eating two servings of low-mercury fish (think salmon, herring, freshwater trout, and anchovies) a week to get the benefit of DHA, an omega-3 fatty acid that helps your baby's brain grow.

"Moms who get a lot of DHA and omega-3s in their diet have better pregnancy outcomes—longer pregnancies, better weight, higher performance on milestones and development—but there's been no evidence that taking these things as a pill recreates the same effects," says Dr. Sullivan. "It seems more dietary sources are important."

That said, DHA is included in many prenatal vitamins these days, too, so even the seafood-averse can get the daily 200 milligrams of DHA March of Dimes recommends.

    What Are the Best Over-the-Counter Prenatal Vitamins?

    These days, prenatal vitamins come in all forms: tablets, capsules, gummies, chewables—even powder and liquid options. Pay special attention to labels if you're taking an alternative formula, as it may be lower in iron, iodine, or DHA. "In general, gummies and chewables have less than the traditional pill because of what they're able to put in the formulation," says Dr. Sullivan.

    Prescription vitamins' formulas vary, and most women don't need one. "The only real difference is the amount of folic acid," says Dr. Levitt. "If you want to take a milligram or more of folic acid in one single tablet, it has to be [in a] prescription vitamin." You might need one if you're carrying multiples or have a history of neural tube defects in the family.

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      What About Side Effects?

      It's ironic that the time when many women can't keep anything down (early pregnancy morning sickness, anyone?) is crucial to getting key nutrients via sometimes bulky and smelly pills. Downing vitamins on an empty stomach can make nausea worse, so try taking them with smooth-textured food you do like (applesauce, smoothies, or ice cream). 

      While there's not much risk of over-supplementing, overdosing on vitamin A, however, can cause birth defects. Skip anything that lists more than 100 percent of the recommended dietary allowance of vitamin A on the back of the bottle, says Dr. Levitt. 

      If you're already experiencing side effects, our guide to prenatal vitamin side effects provides a more comprehensive list of potential symptoms and solutions. 

      When in doubt, ask your doctor about your prenatal vitamin and any other supplements you're taking. You'll want a vitamin you're comfortable with since you shouldn't necessarily drop the pill after delivery. Most doctors recommend taking a prenatal vitamin as long as you're breastfeeding, or even longer if you plan to have another baby soon—a choice that makes picking a vitamin seem like a breeze! 

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