Is Fosfomycin Safe in Pregnancy

Status

caution Last reviewed: 2026-05-16 · Confidence: moderate

Reason

Limited pregnancy data. Official labels say use only if clearly needed and provider review is needed.

Drug Information

Brand Name
Monurol, Contepo
Generic Name
fosfomycin
Drug Class
Antibiotic; phosphonic acid derivative
FDA Category
B
Rx Status
prescription

Safe Amount

Dosage must be determined by your provider based on individual risk/benefit.

Effects

Pregnancy
Human data are limited. Official labeling says use during pregnancy only if clearly needed.
Mother
Used to treat bacterial infections, including UTIs. Side effects may still occur.
Baby
Placental transfer occurs. Animal data did not show malformations, but human data are limited.

Trimester Notes

1st Trimester
A large study found no increased risk of major congenital anomalies with first-trimester exposure, but official data remain limited.
2nd Trimester
No trimester-specific official warning was found in the cited sources; provider review is still needed.
3rd Trimester
No trimester-specific official dosing or warning was found in the cited sources.

Risk-Benefit Note

Treating a confirmed urinary infection in pregnancy can be important for mother and baby. The decision should balance infection risks against limited fetal safety data.

Conditions & Warnings

  • Consult OB/GYN or prescriber
  • Prescription drug: do not start, stop, or continue without provider review
  • Use only if clearly needed per official labeling

Alternatives

  • Nitrofurantoin if appropriate for the infection and gestational age
  • Cephalexin or other beta-lactam options if appropriate
  • Consult your OB/GYN or prescriber for culture-guided treatment

References

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