Is tulsi tea safe during pregnancy?

What does the evidence say about tulsi tea during pregnancy?

1. Safety during pregnancy and lactation has not been investigated for holy basil, and until more is known, it should probably be avoided at those times, according to a pharmacology and phytochemistry overview of the plant. 1
2. Tulsi contains ursolic acid, which animal research has linked to impaired ovum implantation and reduced fertility, and separate rodent studies found similar reversible anti-fertility effects that resolved after the extract was stopped, though none of this has been tested in human pregnancy. 2
3. Tulsi has documented blood-sugar-lowering and blood-clotting effects in research: extracts enhance insulin secretion and lower blood glucose in diabetic animal studies, and a fixed oil from the plant increased blood clotting time to a degree comparable with aspirin, effects that can matter alongside diabetes medication or before a procedure. 2
4. A systematic review of tulsi's clinical safety found favorable outcomes across 24 human studies with only one report of occasional nausea, but the longest trial ran just 13 weeks and none of the studies addressed pregnancy, so this reassurance doesn't extend to pregnant people. 3
5. Herbal products like tulsi are sold as supplements rather than regulated drugs, and a review of herbal medicine use in pregnancy found that most of these products are not tested in clinical trials during pregnancy, so an absence of reported problems in the general population isn't the same as proof of safety in pregnancy. 4

Is tulsi tea safe in each trimester?

• First trimester. The fertility and implantation effects seen in animal studies are most relevant to this early window, which is exactly when a pregnancy pharmacology review says holy basil's safety hasn't been established and it should probably be avoided. Choose a different herbal tea for now.
• Second trimester. There's no research carving out a safer window later in pregnancy: the same absence of human safety data, and the same blood-sugar and blood-clotting effects seen in research, carry through the second trimester. Save regular tulsi tea for after pregnancy and ask your provider first if you're curious about it.
• Third trimester. Tulsi's effect on blood clotting is worth flagging if any procedure or delivery is on the horizon, since research describes an increase in blood coagulation time comparable to aspirin's effect. Mention regular tulsi tea use at a prenatal visit the same way you would an aspirin-like supplement.