Is beta-carotene safe during pregnancy?

What does the evidence say about beta-carotene during pregnancy?

1. Beta-carotene doesn't build up in the body the way preformed vitamin A does, because your body controls the rate at which it converts beta-carotene into usable vitamin A. 1
2. Regulators set a firm upper intake limit of 3,000 mcg RE a day for preformed vitamin A in pregnancy based on its potential to cause birth defects, but could not set an equivalent upper limit for beta-carotene because there wasn't enough dose-response data to show it carries the same risk. 2
3. Typical dietary beta-carotene intake among pregnant women in food-frequency studies runs roughly 3,800 to 4,500 mcg a day from food alone, and the body converts it to vitamin A at only about a 12-to-1 ratio, part of why it doesn't accumulate the way preformed vitamin A can. 3
4. A safety review found no evidence of adverse effects from high carotenoid supplementation or intake in pregnant women, including those who smoke, or in their newborns and infants, though long-term high-dose beta-carotene supplements (around 20 mg a day for years) have been linked to a higher lung cancer rate specifically in men who smoke. 3
5. A systematic review of antioxidant supplements, including those containing beta-carotene, found no proven effect on preeclampsia risk, so beta-carotene shouldn't be relied on for that purpose even though it's a reasonable, well-tolerated part of a normal prenatal vitamin. 4

Is beta-carotene safe in each trimester?

• First trimester. Beta-carotene from food and standard prenatal doses is fine in the first trimester, when the vitamin A concern mainly centers on preformed (retinol) vitamin A, not beta-carotene.
• Second trimester. In the second trimester, most people get beta-carotene from a mix of colorful vegetables and their prenatal vitamin, a reasonable way to help meet vitamin A needs without the buildup risk that comes with preformed vitamin A.
• Third trimester. In the third trimester, beta-carotene needs don't change in a way that calls for extra supplementation beyond a normal prenatal vitamin and a varied diet.