Is biotin safe during pregnancy?

What does the evidence say about biotin during pregnancy?

1. The Adequate Intake for biotin is 30 micrograms a day for pregnant women and 35 micrograms a day for lactating women, and no Tolerable Upper Intake Level has been established because no reported adverse effects have been found in humans or animals, even at doses up to 200 milligrams taken orally. 1
2. Evidence suggests pregnant women likely need biotin intake at least two to three times the standard adequate intake to fully meet the demands of pregnancy, and a study found pregnant women's biotin-deficiency markers improved with supplementation of 300 micrograms a day, about ten times the current adequate intake. 2
3. Roughly half of pregnant women show elevated urinary 3-hydroxyisovaleric acid, a marker of reduced biotin-dependent enzyme activity, indicating marginal biotin deficiency, though the researchers note this finding alone doesn't yet justify widespread biotin supplementation without further evidence directly linking it to fetal effects. 3
4. A case report of a patient taking 10,000 micrograms of biotin daily developed lab results mimicking hyperthyroidism that fully resolved within five days of stopping the supplement, and the authors recommend discontinuing biotin for 48 to 72 hours before thyroid or other biotin-streptavidin-based blood tests. 4
5. Despite the widespread marginal shortfall seen on lab markers, women who develop this degree of biotin deficiency during pregnancy gain weight normally and show no overt physical signs of deficiency, which is part of why researchers describe it as a marginal rather than a severe or clinically obvious deficiency. 2

Is biotin safe in each trimester?

• First trimester. Biotin needs don't spike dramatically in the first trimester, but shortfall markers can show up on labs even this early. A standard prenatal vitamin's biotin content is typically enough to cover it.
• Second trimester. Continue whatever prenatal routine you started. There's no evidence that second-trimester needs jump beyond the pregnancy-wide adequate intake of 30 micrograms a day.
• Third trimester. Needs stay steady through the third trimester. If you're planning to breastfeed, know that the recommended intake rises slightly again after delivery, to 35 micrograms a day.

Biotin intake reference during pregnancy