Is Flagyl Safe During Pregnancy

Status

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

Reason

Official labels do not show increased birth-defect risk, but use in pregnancy needs provider review; first trimester trichomoniasis is contraindicated.

Drug Information

Brand Name
Flagyl
Generic Name
metronidazole
Drug Class
nitroimidazole antibiotic/antiprotozoal
FDA Category
B
Rx Status
prescription

Safe Amount

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

Effects

Pregnancy
First trimester use for trichomoniasis is contraindicated in FDA labeling. Otherwise, use only when needed and reviewed by a prescriber.
Mother
May treat infections that can harm the mother and pregnancy. Side effects can include nausea, metallic taste, and dizziness.
Baby
Crosses the placenta. Human data do not show a clear increase in birth defects, but data are limited.

Trimester Notes

1st Trimester
For trichomoniasis, FDA labeling says this is contraindicated during the first trimester.
2nd Trimester
Use only when the benefit outweighs risk and the prescriber agrees.
3rd Trimester
No specific trimester ban in labeling, but use only if needed and reviewed by a prescriber.

Risk-Benefit Note

If the infection is untreated, it can also harm pregnancy. Do not start, stop, or change treatment without your OB/GYN or prescriber.

Conditions & Warnings

  • Consult OB/GYN or prescriber
  • Trichomoniasis in pregnancy
  • First trimester pregnancy
  • Bacterial vaginosis
  • Breastfeeding review may be needed

Alternatives

  • Ask your OB/GYN about pregnancy-appropriate treatment based on the infection and trimester.
  • For vaginitis, get the exact diagnosis before using any medicine.

References

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