Can Tranexamic Acid Be Given in the First Trimester?
Tranexamic acid should be avoided during the first trimester of pregnancy due to insufficient safety data, with two reported cases of infant structural abnormalities resulting in death when used during conception or first trimester, though causality remains unclear. 1
Safety Profile in First Trimester
The FDA drug label explicitly states that available data have not clarified whether tranexamic acid carries a drug-associated risk of miscarriage or adverse maternal or fetal outcomes, and specifically notes 2 (0.02%) infant cases with structural abnormalities resulting in death when tranexamic acid was used during conception or the first trimester. 1 However, the label acknowledges that due to confounding factors, the risk of major birth defects with first trimester use is not clear. 1
Guideline Recommendations for Pregnancy Use
For hereditary angioedema management during pregnancy, tranexamic acid could be considered only after the first trimester when C1-INH is not available, as evidence of efficacy and safety—particularly regarding teratogenicity and thrombosis risk—is lacking. 2
Placental Transfer Considerations
Tranexamic acid is known to pass through the placenta, with cord blood concentrations approximately equal to maternal blood concentrations (about 30 mg/L after 10 mg/kg IV injection). 1 This complete placental transfer raises theoretical concerns about fetal exposure during organogenesis in the first trimester.
Animal Reproduction Data
Animal studies in mice, rats, and rabbits at doses up to 3-6 times the maximum human dose based on body surface area have not revealed adverse effects on the fetus when administered during organogenesis. 1 However, animal data cannot fully predict human teratogenic risk.
Clinical Context and Risk-Benefit Assessment
The FDA label emphasizes that for decisions regarding tranexamic acid use during pregnancy, the potential risk to the fetus should always be considered along with the mother's clinical need, and an accurate risk-benefit evaluation should drive the treating physician's decision. 1
Approved Indications During Pregnancy
Tranexamic acid is only recommended for use during pregnancy in specific clinical scenarios:
- Postpartum hemorrhage treatment: Should be administered within 3 hours of birth at 1g IV over 10 minutes, with possible second dose if bleeding continues. 2, 3, 4
- Second and third trimester use: Available data from published studies in the second and third trimester and at delivery have not clarified drug-associated risks. 1
Critical Safety Caveat
There are no approved indications for tranexamic acid use during the first trimester, and the drug should only be used when the mother's clinical need clearly outweighs the uncertain fetal risk. 1