Tetracycline has been assigned to pregnancy category D by the FDA. Animal studies have revealed evidence of embryotoxicity and teratogenicity, including toxic effects on skeletal formation. There are no controlled data in human pregnancy, however, congenital defects and maternal hepatotoxicity have been reported. When used during tooth development (second half of pregnancy) tetracyclines may cause permanent yellow-gray-brown discoloration of the teeth and enamel hypoplasia. The use of tetracycline during pregnancy is generally not recommended, especially during the last half of pregnancy.

See references

Tetracycline is excreted into human milk in small amounts. Theoretical risks of dental staining and inhibition of bone growth exist, although are unlikely. In one study, tetracycline levels were undetectable in nursing infants. Tetracycline is considered compatible with breast-feeding by the American Academy of Pediatrics. However, the manufacturer recommends that because of the risk of serious potential adverse reactions in nursing infants, a decision should be made whether to continue breast-feeding or discontinue the drug, taking into account the importance of the drug to the mother.

See references