All About Prenatal Vitamins — Your Questions Answered

A good prenatal vitamin helps you get necessary nutrients your diet may lack.


Though it won't replace healthy eating, a prenatal supplement is essential. Here's expert advice to help you choose a good one.

Q: How early in my pregnancy should I begin taking a prenatal vitamin?

A: Start three months before you begin trying to get pregnant, if possible. "The egg starts maturing about three months before it's released, and it's critical that the proper nutrients are present during the earliest stages," says OB-GYN Robert Greene, M.D., medical director of the Sher Institute for Reproductive Medicine in Sacramento, Calif. "Neural-tube defects [such as spina bifida] happen in the first four to six weeks of pregnancy," says Sudeep Kukreja, M.D., associate director of the Neonatal Intensive Care Unit at CHOC Children's in Orange, Calif. If you think you're pregnant and are not taking a supplement, don't wait until your first appointment for a prescription because you will have missed this critical developmental period. Start taking an over-the-counter folic acid supplement with 600 micrograms (mcg) right away.

Q: What are the most important vitamins and minerals and why?

A: "The three most important nutrients, based on very good research, are folic acid, iron and calcium," says Kukreja. Folic acid helps prevent neural-tube defects; iron is important for the delivery of oxygen to the baby and prevents anemia in the mom; and calcium helps build your baby's bones and prevents bone loss in the mother.

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Q: Are all varieties of prenatal vitamins pretty much the same?

A: No. Prescription vitamins are regulated by the Food and Drug Administration, but they are not required to contain certain nutrients. "There are many different formulations available, with different concentrations of each nutrient," says Kukreja. Some have a little of everything; others contain only a handful of nutrients. If you have special health considerations, your OB may suggest a supplement with added nutrients to meet your needs. Q: Can I take an over-the-counter or organic prenatal vitamin?

A: There's nothing wrong with taking over-the-counter vitamins as long as they have a USP (U.S. Pharmacopeia) seal or NSF International certification; these organizations monitor supplement quality. "We do have concerns about pills that contain certain herbs and those that may contain too much of a certain nutrient, like vitamin A, which can adversely affect the fetus' development," says Ashlesha Dayal, M.D., an associate professor of obstetrics and gynecology at the Montefiore Medical Center in Bronx, N.Y. "Take the bottle to your obstetrician to make sure that all the ingredients are safe," Kukreja adds.

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Q: Is it necessary to take anything in addition to my prenatal vitamin?

A: "Supplement with calcium if your prenatal doesn't contain enough," says Kukreja. Most don't because adding too much calcium to a multivitamin makes it unstable. Pregnant women need 1,000 milligrams (mg) a day; many supplements only contain 150 to 250 milligrams. You can take a Tums tablet daily to supplement it.

Additionally, a recent study found that many pregnant women are deficient in vitamin D. A supplement containing 200 IU will give you your daily dose, as will getting five to 30 minutes of sun exposure without sunscreen, at least twice a week.

What's more, the World Association of Perinatal Medicine recommends that pregnant women get at least 200 milligrams of DHA daily. Found in fish and some vegetarian sources, DHA is an omega-3 fatty acid that's essential to fetal brain development. Many prenatals contain DHA. You also can take a fish oil capsule; they're mercury-free.

Q: I recently learned that iodine is important. Do prenatals contain it? If not, do I need a supplement?

A: Some do and some don't; be sure to check the label of any supplement you take. "Based on current knowledge, it's not recommended," says Kukreja. That may change in the future, but for now you can get iodine from iodized salt. Pregnant women should get 220 micrograms a day. A half teaspoon of iodized salt contains 190 micrograms, and the median intake women get from food daily is 190 to 210 micrograms.

Q: I'm a vegetarian. Should I be taking any additional supplements?

A: "Because [strict] vegetarians are not consuming animal products, the nutrients they tend to need are vita-min B12, zinc, iron and omega-3 fatty acids like DHA," says Greene. "Look for supplements that contain these vitamins plus DHA from algae, a vegetarian source, rather than from fish."

Q: What should I do if I have morning sickness and am throwing up?

A: "Try to take the vitamin before you go to bed at night, so you can sleep through the nausea," says Dayal.

Important nutrients for pregnant women:

NUTRIENT RDA Calcium 1,000 mg DHA 200 mg Folic acid 600 mcg Iodine 220 mcg Iron 27 mg Vitamin B6 1.9 mg Vitamin B12 2.6 mcg Vitamin C 80 mg Vitamin D 200 IU Vitamin E 15 mg Zinc 11 mg