Is riboflavin safe during pregnancy?

What does the evidence say about riboflavin during pregnancy?

1. The recommended dietary allowance for riboflavin during pregnancy is 1.4 milligrams a day, compared with 1.1 milligrams a day for nonpregnant adult women. 1
2. No tolerable upper intake level has been set for riboflavin, because there isn't enough evidence of harm from high intakes to calculate one, unlike nutrients such as vitamin A that do carry a defined upper limit in pregnancy. 1
3. The dietary reference intake summary table confirms the same figures, a 1.4 milligram daily allowance for pregnant women age 19 to 50, versus 1.1 milligrams for nonpregnant women in that age range. 2
4. A randomized trial that tracked riboflavin status found that without supplementation, blood riboflavin levels declined from early to late pregnancy, with the great majority of participants showing marginal riboflavin status by late pregnancy. A 1.8 milligram daily supplement, the amount in many prenatal vitamins, reliably raised levels back up. 3
5. Riboflavin deficiency has also been studied as a possible risk factor for high blood pressure in pregnancy, with one study finding a nearly three-fold higher risk of pregnancy hypertension among people with low riboflavin status, though a separate clinical trial found no difference in preeclampsia rates with riboflavin supplementation, so this connection is still being researched. 4

Is riboflavin safe in each trimester?

• First trimester. Riboflavin needs rise as soon as pregnancy begins, and your prenatal vitamin is typically formulated to cover the increase, so most people don't need to think about riboflavin separately in the first trimester.
• Second trimester. Research following riboflavin levels through pregnancy has found they tend to decline from early to late pregnancy without supplementation, which is part of why prenatal vitamins are formulated to keep providing riboflavin throughout.
• Third trimester. Riboflavin status keeps dropping through the third trimester in people who aren't supplementing, so continuing your prenatal vitamin through the end of pregnancy, not just the first trimester, is the simplest way to stay covered.

Riboflavin recommended intake