Tetracycline

Pregnancy

Tetracycline crosses the placenta so when taken during pregnancy it is transferred to the fetus. Repeated or long-term use of tetracycline during pregnancy may lead to a permanent discoloration of teeth in the baby because tetracycline accumulates in teeth and bones. 

Category: D 

Category A

Adequate and well-controlled studies have failed to demonstrate a risk to the fetus in the first trimester of pregnancy (and there is no evidence of risk in later trimesters).

Category B

Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

Category C

Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Category D

There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Category X

Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.

Breastfeeding

Excretion into human milk: Yes

Prolonged or repeated use of tetracycline should be avoided during breastfeeding. Tetracycline is excreted into breast milk possibly causing discoloration of teeth. Tetracycline may also disturb the normal gut bacteria in the baby causing diarrhea or a fungal infection (such as thrush and diaper rash).