Famotidine Use During Pregnancy
Famotidine is safe to use during pregnancy as available data show no increased risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. 1
Safety Profile
- Famotidine is classified as FDA Pregnancy Category B, indicating animal studies have not demonstrated fetal risk, but there are no adequate controlled studies in pregnant women 2
- The FDA drug label states that in animal reproduction studies, no adverse developmental effects were observed with oral administration of famotidine at doses up to approximately 243 and 122 times the recommended human dose 1
- Reproductive studies in rats and rabbits at high oral doses revealed no significant evidence of impaired fertility or harm to the fetus due to famotidine 1
Clinical Evidence
- A 2024 observational cohort study found no significant difference in the incidence of congenital malformations between pregnant women who took famotidine during the first trimester (3.9%) and control groups (2.8%) 3
- While this study initially showed a higher rate of preterm delivery in the famotidine group (8.1% vs 3.8% in controls), multivariate analysis eliminated famotidine use as a confounding factor 3
- A 2005 collaborative study by the European Network of Teratology Information Services evaluating H2-blockers in pregnancy found no increased risk of major malformations with famotidine use 4
Pharmacokinetic Considerations
- A 2025 PBPK/PD modeling study indicated that famotidine exposure decreases by approximately 24% in mid-pregnancy and 20% in late pregnancy compared to non-pregnant women 5
- Despite these pharmacokinetic changes, the model suggested that famotidine maintains its effect on increasing intragastric pH in pregnant women similar to non-pregnant adults 5
Recommendations for Use
- When antihistamine therapy is necessary during pregnancy, H2-blockers like famotidine can be considered safe options 2
- Famotidine can be used for the treatment of heartburn and gastroesophageal reflux disease, which are common during pregnancy 5
- The benefit of treating significant gastrointestinal symptoms during pregnancy generally outweighs the potential risks of famotidine use 6
Important Considerations
- As with all medications during pregnancy, the use of famotidine should balance maternal benefit against any potential risk 2
- The background risk for major birth defects in the general U.S. population is 2-4%, and miscarriage is 15-20% in clinically recognized pregnancies 1
- Limited data are available on famotidine presence in human breast milk, but studies indicate no effects on breastfed infants 1
Conclusion
Based on the available evidence, particularly the FDA drug label and recent observational studies, famotidine appears to be safe for use during pregnancy with no demonstrated increased risk of congenital malformations or adverse pregnancy outcomes.