Is doxycycline (a tetracycline antibiotic) safe to use during pregnancy?

Doxycycline Safety in Pregnancy

Doxycycline is contraindicated during pregnancy due to risks of permanent tooth discoloration, inhibition of bone growth in the fetus, and potential embryotoxicity. 1, 2

Risks of Doxycycline Use During Pregnancy

• Doxycycline is classified as FDA Pregnancy Category D, indicating there is positive evidence of human fetal risk 1
• Tetracycline-class drugs, including doxycycline, can cause permanent yellow-gray-brown discoloration of teeth when used during tooth development (last half of pregnancy) 1
• These drugs form a stable calcium complex in bone-forming tissue, potentially affecting fetal skeletal development 1
• Animal studies indicate tetracyclines cross the placenta, are found in fetal tissues, and can have toxic effects on the developing fetus 1

Guidelines and Recommendations

• Multiple guidelines strongly recommend avoiding doxycycline during pregnancy 2
• The European Respiratory Journal (2020) classifies doxycycline as "possibly safe" during the first trimester but recommends avoiding it during the second and third trimesters 2
• The MMWR Recommendations (2016) states that tetracyclines are generally contraindicated during pregnancy due to risks of malformation of teeth and bones in the fetus 2
• The North American Clinical Practice Guidelines for Hidradenitis Suppurativa (2025) strongly recommends against oral doxycycline during pregnancy due to potential increased risk of congenital anomalies 2

Alternative Antibiotics During Pregnancy

• When antibiotics are needed during pregnancy, safer alternatives include:
  • Cephalexin 2
  • Azithromycin 2
  • Amoxicillin 3
  • Rifampin (for specific indications) 2, 3

Emerging Evidence on Doxycycline Safety

• Some recent research suggests the teratogenic risk of doxycycline may be lower than previously thought:
  • A 1997 study found that doxycycline treatment during pregnancy presents very little if any teratogenic risk to the fetus 4
  • A 2016 review suggested doxycycline's safety profile differs significantly from tetracycline, with no correlation found between doxycycline use and teratogenic effects during pregnancy 5
  • A 2025 large population-based cohort study found no association between first-trimester doxycycline exposure and increased major congenital malformation risk 6

Special Considerations

• In life-threatening situations where clinical suspicion of tickborne rickettsial disease is high, the benefits of doxycycline may outweigh the potential risks to the fetus 2
• Patient counseling and discussion of potential risks versus benefits with the pregnant woman are important components in treatment decision-making 2
• For tick-borne diseases during pregnancy, alternative treatments should be considered:
  • Chloramphenicol for Rocky Mountain Spotted Fever (with caution in late third trimester) 2
  • Rifampin for mild anaplasmosis 2, 3

Conclusion

Despite some emerging evidence suggesting lower teratogenic risk, current guidelines and FDA labeling still contraindicate doxycycline use during pregnancy due to potential risks to fetal development. Alternative antibiotics should be used whenever possible, with doxycycline reserved only for life-threatening situations where benefits clearly outweigh risks.