Why you need vitamin A during pregnancy
Vitamin A is a fat-soluble vitamin that's stored in the liver. Vitamin A is important for your baby's embryonic growth, including the development of the heart, lungs, kidneys, eyes, and bones as well as the circulatory, respiratory, and central nervous systems.
Vitamin A is particularly essential for women who are about to give birth because it helps with postpartum tissue repair. It also helps maintain normal vision, fights infections, supports your immune system, and helps with fat metabolism.
Understanding vitamin A
There are two types of the nutrient: preformed vitamin A and provitamin A carotenoids. Preformed vitamin A (also called retinol) is used directly by the body and is found in animal products like eggs, milk, and liver. Provitamin A carotenoids are found in fruits and vegetables, but your body must convert this type into retinol.
More than 600 carotenoids are found in nature, but only a few can be converted to retinol. Beta-carotene is the most common one.
The standard of measurement for vitamin A is RAE (retinol activity equivalents), which is based on the potency and source of vitamin A. One microgram (mcg) of retinol (preformed vitamin A) is equal to 1 mcg RAE, but it takes 12 mcg of beta-carotene or 24 mcg of alpha-carotene to equal 1 mcg RAE.
An older standard of measurement that is still used (especially on Supplement Facts labels) is the International Unit, or IU. IUs aren't easily converted to RAE because the conversion depends on the type of vitamin A. For example, 900 mcg RAE could be anywhere from 6,000 to 36,100 IU of vitamin A.
How much vitamin A you need
Pregnant women age 18 and younger: 750 mcg RAE per day
Pregnant women age 19 and older: 770 micrograms RAE per day
Breastfeeding women age 18 and younger: 1,200 mcg RAE per day
Breastfeeding women age 19 and older: 1,300 mcg RAE per day
Nonpregnant women: 700 mcg RAE per day
You don't have to get the recommended amount of vitamin A every day. Instead, aim for that amount as an average over the course of a few days or a week.
Can you get too much vitamin A?
The average American diet provides plenty of vitamin A. It's available in meat, dairy, fish, eggs, and fortified cereals in the form of preformed vitamin A, or retinol. It's also in most fruits and vegetables, mostly in the form of carotenoids.
During pregnancy, it's important not to get too much preformed vitamin A, which can cause birth defects and liver toxicity in high doses. (However, you can get as many carotenoids as you want from fruits and vegetables.)
Women age 19 and older – whether or not they're pregnant or breastfeeding – should get no more than 3,000 mcg RAE (or 10,000 IU) of preformed vitamin A from supplements, animal sources, and fortified foods each day. For women age 18 and younger, the upper intake limit is 2,800 mcg RAE (9,333 IU).
This is one important reason why it's not a good idea to double up on your prenatal vitamins or take any supplements that your practitioner doesn't recommend. Most prenatal vitamins contain at least part of their vitamin A in the form of beta-carotene, but some over-the-counter brands, other kinds of multivitamins, and some fortified foods contain significant amounts of preformed vitamin A. Always check a product's label or show all supplements to your practitioner before taking them.
One more thing: The risk of birth defects from getting too much vitamin A is the reason that pregnant women and those trying to conceive should stay away from the prescription acne drug isotretinoin (also known by the brand name Accutane, among others) and other drugs related to retinol (a compound of vitamin A), including topical tretinoin (Retin-A), which is used for skin conditions.
Food sources of vitamin A
Fruits and vegetables (particularly orange and yellow ones and leafy greens), rich in beta-carotene, are the best sources of vitamin A. You're also likely to get a fair amount of preformed vitamin A from fortified milk and cereals.
Liver (from beef, veal, or chicken, for example, and including pâtés and liverwurst) contains the highest amounts of preformed vitamin A – so much that you should limit it to once or twice a month during pregnancy to be sure that you don't get too much at once. A 3-ounce serving of beef liver can contain more than eight times the recommended daily amount of vitamin A during pregnancy – more than twice the amount that's safe to consume in one day!
Here are some good food sources of vitamin A:
- one medium baked sweet potato: 961 mcg RAE (19,218 IU)
- 1/2 cup canned pumpkin: 953 mcg RAE (19,065 IU)
- 1/2 cup butternut squash, cooked: 572 mcg RAE (11,434 IU)
- 1/2 cup canned sweet potato, mashed: 555 mcg RAE (11,091 IU)
- 1/2 cup raw carrot, chopped: 534 mcg RAE (10,692 IU)
- 1/2 cup spinach, cooked: 472 mcg RAE (9,433 IU)
- 1/2 medium cantaloupe: 466 mcg RAE (9,334 IU)
- 1/2 cup kale, cooked: 443 mcg RAE (8,854 IU)
- 1/2 cup collard greens, cooked: 361 mcg RAE (7,220 IU)
- 1 ounce fortified oat cereal: 215 mcg RAE (721 IU)
- one mango: 181 mcg RAE (3,636 IU)
- 8 ounces nonfat milk (vitamin A added): 149 mcg RAE (500 IU)
- 8 ounces 2% fat milk (vitamin A added): 134 mcg RAE (464 IU)
- 8 ounces whole milk: 110 mcg RAE (395 IU)
- 1 tablespoon butter: 95 mcg RAE (355 IU)
- one large egg: 80 mcg RAE (270 IU)
- 1/2 cup cooked broccoli: 60 mcg RAE (1,207 IU)
Both processing (like chopping, grating, or juicing) and cooking food make provitamin A carotenoids easier for your body to absorb. You'll also absorb more if you eat a small amount of fat (about a teaspoon) at the same time.
Should you take a vitamin A supplement?
Probably not. Most people get plenty of vitamin A from their diet, and prenatal vitamins also usually contain vitamin A. Read the label on yours to make sure that you're not getting more than the recommended amount, and that it's not all the preformed version.
If you think you need a vitamin A supplement, or if you have questions about the vitamin A in your prenatal supplement, ask your healthcare provider for guidance.
Signs of a vitamin A deficiency
Because it's easy to get enough vitamin A from your diet, Vitamin A deficiencies in the United States are rare, except as a result of some medical conditions. Signs of a deficiency include impaired night vision and a weakened immune system. People who are deficient may also develop a condition called xerophthalmia, which results in a cornea that becomes dry and thick.