Famotidine
MedicationPepcid
H2-receptor antagonist
Research strength: 3 / 5
MotherToBaby reports that pregnancy studies have not found an increased chance of birth defects. A Japanese cohort study reported birth defects in 13 of 330 births with first-trimester famotidine exposure (3.9%) and 40 of 1,407 comparison births (2.8%); the adjusted result was not statistically significant. The same study reported miscarriage in 14 of 372 famotidine pregnancies (3.8%) and 70 of 1,576 comparison pregnancies (4.4%), with no difference noted, although MotherToBaby says miscarriage had not been studied. The PEPCID prescribing information says human data are insufficient to establish pregnancy risks and says famotidine should be used only if clearly needed. Ask your provider about your situation.
Last reviewed: 2026-10-16
Research strength: 3 / 5
MotherToBaby reports no increased chance of birth defects in pregnancy studies but says preterm delivery and low birth weight had not been studied. A 2024 Japanese cohort assessed those outcomes for famotidine use at any pregnancy stage: preterm birth before 37 weeks occurred in 28 of 347 famotidine pregnancies (8.1%) and 56 of 1,476 comparisons (3.8%); birth weight under 2,500 g occurred in 46 of 347 (13.3%) and 101 of 1,476 (6.8%). The researchers noted more maternal complications in the famotidine group and said these could explain the preterm difference; results were not specific to second-trimester use. The PEPCID prescribing information says human data are insufficient to establish pregnancy risks and says famotidine should be used only if clearly needed. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Famotidine fact sheetTeratology service
- Nishimura et al., Effects of famotidine use during pregnancy: an observational cohort studyUS government
- Gill et al., The safety of histamine 2 (H2) blockers in pregnancy: a meta-analysisUS government
- PEPCID (famotidine) tablets, DailyMed prescribing informationDrug company label
Research strength: 3 / 5
MotherToBaby reports no increased chance of birth defects in pregnancy studies but says preterm delivery and low birth weight had not been studied. A 2024 Japanese cohort assessed those outcomes for famotidine use at any pregnancy stage: preterm birth before 37 weeks occurred in 28 of 347 famotidine pregnancies (8.1%) and 56 of 1,476 comparisons (3.8%); birth weight under 2,500 g occurred in 46 of 347 (13.3%) and 101 of 1,476 (6.8%). The researchers noted more maternal complications in the famotidine group and said these could explain the preterm difference; results were not specific to third-trimester use. The PEPCID prescribing information says human data are insufficient to establish pregnancy risks and says famotidine should be used only if clearly needed. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: Famotidine fact sheetTeratology service
- Nishimura et al., Effects of famotidine use during pregnancy: an observational cohort studyUS government
- Gill et al., The safety of histamine 2 (H2) blockers in pregnancy: a meta-analysisUS government
- PEPCID (famotidine) tablets, DailyMed prescribing informationDrug company label
Famotidine — Breastfeeding
Research strength: 3 / 5
LactMed reports that milk levels result in infant doses below amounts used to treat newborns and says no special precautions are required. MotherToBaby also reports small amounts in milk and says problems are not expected; the NHS Specialist Pharmacy Service says famotidine can be used during breastfeeding but advises monitoring for diarrhea, constipation, irritability, drowsiness, or rash in full-term, healthy infants. A UK famotidine product label takes a more cautious position and advises mothers to stop the medicine or stop breastfeeding because famotidine enters milk. LactMed says published infant-level and infant-outcome information was not found, so direct infant outcome evidence remains limited. Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- LactMed: FamotidineUS government
- MotherToBaby: Famotidine fact sheetTeratology service
- NHS Specialist Pharmacy Service: Treating heartburn and dyspepsia during breastfeedingUK government
- PEPCID (famotidine) tablets, DailyMed prescribing informationDrug company label
- Famotidine 20 mg Tablets, Summary of Product Characteristics
Pregnancy
Nishimura et al. (2024) used pregnancy outcome records from two Japanese counseling centers. For first-trimester exposure, malformations were reported in 13 of 330 live births (3.9%) with famotidine and 40 of 1,407 comparison births (2.8%); the adjusted odds ratio was 1.06 (95% CI 0.51 to 2.16), not statistically significant. Across the full-pregnancy outcome group, miscarriage was reported in 14 of 372 famotidine pregnancies (3.8%) and 70 of 1,576 comparison pregnancies (4.4%); the authors noted no difference. The same study found higher unadjusted rates of preterm birth before 37 weeks (28 of 347, 8.1%, versus 56 of 1,476, 3.8%) and birth weight under 2,500 g (46 of 347, 13.3%, versus 101 of 1,476, 6.8%). The authors noted more inflammatory autoimmune illness among famotidine users, said this could explain the preterm finding, and called for more study. The outcomes were not reported separately for each later trimester. Gill et al. (2009) pooled 2,398 H2-blocker-exposed and 119,892 unexposed pregnancies and did not find increased risks for spontaneous abortion, preterm delivery, or small-for-gestational-age birth, but those results were for the drug class, not famotidine alone. Matok et al. (2010) studied 1,148 first-trimester exposures to H2 blockers as a group and likewise reported no association with major malformations or several other outcomes. Liu et al. (2025) built a pharmacokinetic model, not an outcome study, and predicted lower famotidine exposure in mid and late pregnancy; the authors noted that more clinical data are needed.
Breastfeeding
LactMed summarizes human milk-level studies and reports low transfer, with estimated infant doses below those used to treat newborns. It states that published infant-level and infant-outcome information was not found in its evidence review. MotherToBaby also describes small amounts in milk and says problems are not expected. NHS Specialist Pharmacy Service says the published evidence is limited, no infant side effects have been reported, and famotidine can be used during breastfeeding with precautionary monitoring. Its recommendations apply to full-term, healthy infants. The UK product label gives more cautious advice because famotidine enters milk, while LactMed, MotherToBaby, and NHS Specialist Pharmacy Service emphasize low transfer and the lack of reported infant effects.
The PEPCID prescribing information identifies famotidine as a histamine-2 receptor blocker and says its main action is to reduce stomach acid. The label lists 20 mg and 40 mg tablets and describes famotidine as a competitive inhibitor of histamine-2 receptors.
What was tested
The 2024 Japanese cohort used data collected from 1988 through 2017. It analyzed first-trimester malformations among 330 famotidine-exposed live births and 1,407 comparison births, and pregnancy-wide outcomes among 372 famotidine pregnancies and 1,576 comparison pregnancies. For preterm birth and birth weight, the final analysis included 347 and 1,476 singleton pregnancies, respectively. Matok et al. (2010) linked Israeli health-system prescription and hospital records and analyzed 1,148 first-trimester exposures to H2 blockers as a group. Gill et al. (2009) performed a meta-analysis of 2,398 H2-blocker-exposed and 119,892 unexposed pregnancies. Liu et al. (2025) evaluated a physiologically based pharmacokinetic/pharmacodynamic model using clinical data from the literature; it did not measure pregnancy outcomes. For breastfeeding, LactMed summarizes small milk-level studies but reports no published infant-level or infant-outcome data in its evidence review.
Pregnancy evidence and preterm birth
- Source A says
- MotherToBaby reports that pregnancy studies have not found an increased chance of birth defects. The 2024 famotidine-specific cohort found no statistically significant adjusted increase in first-trimester malformations, but it observed higher crude rates of preterm birth and low birth weight across full-pregnancy exposure groups. (MotherToBaby: Famotidine fact sheet, Nishimura et al., Effects of famotidine use during pregnancy: an observational cohort study)
- Source B says
- The PEPCID prescribing information says available human data are insufficient to establish pregnancy risks and says use should be limited to situations where it is clearly needed. The UK product information says famotidine is not recommended in pregnancy unless clearly needed. (PEPCID (famotidine) tablets, DailyMed prescribing information, Famotidine 20 mg Tablets, Summary of Product Characteristics)
- Why they differ
- The fact sheet and cohort summarize reassuring malformation findings, while the product labels emphasize that human evidence is limited. The 2024 cohort also found crude preterm and low-birth-weight differences, but it identified maternal complications that may confound the association. The study did not give reliable outcome estimates for each trimester.
- Other sources
- A 2009 meta-analysis of H2 blockers as a class did not find increased risks for preterm delivery or small-for-gestational-age birth. (Gill et al., The safety of histamine 2 (H2) blockers in pregnancy: a meta-analysis)
- What the evidence shows overall
- The available cohort data do not establish that famotidine causes birth defects, miscarriage, preterm birth, or low birth weight. The crude preterm and low-birth-weight signal should be disclosed, while the limited human data and product-label caution support a guidance rating rather than an avoid rating.
Breastfeeding advice and direct infant-outcome data
- Source A says
- LactMed and MotherToBaby describe low milk transfer and do not expect problems in breastfed infants. NHS Specialist Pharmacy Service says famotidine can be used during breastfeeding, with precautionary monitoring for full-term, healthy infants. (LactMed: Famotidine, MotherToBaby: Famotidine fact sheet, NHS Specialist Pharmacy Service: Treating heartburn and dyspepsia during breastfeeding)
- Source B says
- The UK famotidine product information says famotidine enters human milk and advises breastfeeding mothers to stop famotidine or stop breastfeeding. (Famotidine 20 mg Tablets, Summary of Product Characteristics)
- Why they differ
- The UK product label takes a precaution based on milk excretion. LactMed reports that published infant-level and infant-outcome information was not found, while specialist lactation guidance considers the measured transfer small and recommends monitoring as a precaution.
- Other sources
- The US PEPCID label states that no effects on the breastfed infant were reported, but also says human milk data are limited and gives no details about the infant-outcome evidence. (PEPCID (famotidine) tablets, DailyMed prescribing information)
- What the evidence shows overall
- LactMed, MotherToBaby, and NHS Specialist Pharmacy Service support compatible use, while direct infant-outcome evidence remains limited and a UK product label is more cautious. Under R1, the rating stays compatible and the disagreement is shown; the NHS monitoring note and its full-term, healthy-infant limit are retained.
- MotherToBaby advises discussing the benefits of treating the condition and the risks of untreated illness with a healthcare provider before making medication changes. (MotherToBaby)
- NHS Specialist Pharmacy Service says its breastfeeding recommendations apply to full-term, healthy infants and advises precautionary monitoring for diarrhea, constipation, irritability, drowsiness, or rash. (NHS Specialist Pharmacy Service)
General research, not specific to pregnancy.
The PEPCID label lists headache, dizziness, constipation, and diarrhea among common adverse reactions. It also calls for dosage adjustment with moderate to severe kidney impairment and lists serious hypersensitivity to famotidine or other H2 blockers as a contraindication.
- In seven clinical trials involving about 2,500 patients, 1,442 received PEPCID. The label reports headache, dizziness, and constipation in at least 1% of treated patients. (PEPCID (famotidine) tablets, DailyMed prescribing information)
- The label contraindicates PEPCID for patients with a history of serious hypersensitivity reactions to famotidine or another H2 receptor antagonist and recommends dosage adjustment for moderate to severe renal impairment. (PEPCID (famotidine) tablets, DailyMed prescribing information)
- MotherToBaby: Famotidine fact sheetTeratology serviceSecondaryIndependent check
- LactMed: FamotidineUS governmentSecondaryPage dated 2024-08-15Independent check
- PEPCID (famotidine) tablets, DailyMed prescribing informationDrug company labelTertiaryPage dated 2024-08-09
- Famotidine 20 mg Tablets, Summary of Product CharacteristicsTertiaryPage dated 2025-01-22
- NHS Specialist Pharmacy Service: Treating heartburn and dyspepsia during breastfeedingUK governmentSecondaryPage dated 2024-03-05Independent check
- Nishimura et al., Effects of famotidine use during pregnancy: an observational cohort studyUS governmentPrimaryPage dated 2024-11-08Independent check
- Matok et al., The safety of H(2)-blockers use during pregnancyUS governmentPrimaryPage dated 2010-01-13Independent check
- Gill et al., The safety of histamine 2 (H2) blockers in pregnancy: a meta-analysisUS governmentPrimaryPage dated 2009-09-05Independent check
- Liu et al., Physiologically based Pharmacokinetic/Pharmacodynamic Modeling of Famotidine in PregnancyUS governmentPrimaryPage dated 2025-01-10
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.
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