Objective: This study evaluated the outcome of infants exposed to tranexamic acid during lactation. Subjects and Methods: A prospective, controlled observational study design was used. Mothers who contacted the Beilinson Teratology Information Service (BELTIS) regarding use of tranexamic acid while breastfeeding were followed up by phone interview. Data on lactation, neonatal symptoms, and outcomes at the age of 1-3 years were obtained. Mothers' breastfeeding while taking tranexamic acid and their infants were compared with those of a matched control group of breastfeeding mothers using a drug known to be safe during lactation (amoxicillin) and their infants. Results: Follow-up was obtained for 28 of 32 women who sought advice regarding use of tranexamic acid during breastfeeding. Of the 28 women, six did not take the drug, and one refused to participate. The 21 remaining women (study group) were compared with 42 control women. A decreased amount of breastmilk was reported by one woman in the study group versus two women in the control group (p=1.0). Possible adverse drug effects were reported for one of 21 study group infants (restlessness) and for one of 42 control group infants (gastroesophageal reflux) (p=1.0). Growth below the 3rd percentile was found in one of 21 study group infants versus four of 42 control group infants (p=0.66). Development was normal for all study group infants. Conclusions: No increase in adverse long-term outcomes was found in infants exposed through breastfeeding to tranexamic acid. Our data in conjunction with previous estimates of very low drug exposure support continuation of breastfeeding in women requiring treatment with tranexamic acid.