Why you need iodine during pregnancy
Iodine is essential to the development of your baby's brain and nervous system. It also regulates your baby's metabolism (the rate at which the body uses energy).
Iodine plays an important role in regulating your thyroid gland. A lack of iodine during pregnancy has been linked with an increased risk of miscarriage, preterm delivery, and stillbirth.
How much iodine you need
Pregnant women: 220 micrograms (mcg) per day
Breastfeeding women: 290 mcg per day
Nonpregnant women: 150 mcg per day
You don't have to get the recommended amount of iodine every day. Instead, aim for that amount as an average over the course of a few days or a week.
Food sources of iodine
Iodine is found in dairy products, eggs, vegetables, seafood, and brewer's yeast. (The amount of iodine in many types of food varies according to the amount of iodine in the area's soil or water.)
Good food sources of iodine include:
- 1 cup milk: 99 mcg
- 3 ounces cod: 99 mcg
- 1 gram iodized salt (about 1/8 teaspoon): 77 mcg
- one medium baked potato with skin: 60 mcg
- 3 ounces shrimp: 35 mcg
- two fish sticks: 35 mcg
- 3 ounces turkey breast, baked: 34 mcg
- 1/2 cup cooked navy beans: 32 mcg
- 3 ounces tuna, canned in oil: 17 mcg
- one large egg, hard boiled: 12 mcg
(Note: Sea vegetables contain large amounts of iodine – sometimes even too much for regular consumption. Just one-quarter of an ounce of dried seaweed can contain more than 4,500 mcg of iodine, which is more than four times the tolerable upper intake level. The maximum amount considered safe by the Food and Nutrition Board of the Institute of Medicine is 1,100 mcg per day.)
Should you take an iodine supplement?
Prenatal vitamins don't contain a reliable amount of iodine, but you probably still won't need to take a supplement because it's easy to meet your requirement with food.
In the United States, about half of all table salt is enriched with iodine to prevent iodine deficiencies. Read the label to make sure. Also check the amount because it can vary widely. (Sea salt doesn't always contain iodine, and the salt in processed food is rarely iodized.)
In general, Americans get more than enough salt in their diets: The Centers for Disease Control estimates that the average American gets about 48 percent more salt than recommended. Still, you might want to tally your iodine intake for a day to make sure you're getting enough.
The signs of an iodine deficiency
Iodine deficiencies are uncommon in the United States, but worldwide, iodine deficiencies are the single most important cause of preventable intellectual disability and brain damage.
Signs of thyroid problems from a lack of iodine include an enlarged thyroid gland, fatigue, weakness, depression, intolerance to cold, and weight gain. If you're concerned that you may have an iodine deficiency, talk with your doctor or midwife.