This drug is only recommended for use during pregnancy when there are no alternatives and the benefit outweighs risk to the fetus.

US FDA pregnancy category: C

Comments:
-If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.
-Amoxicillin may affect combined oral estrogen/progesterone contraceptive efficacy.

Animal studies using amoxicillin have failed to reveal evidence of fetal harm and/or impaired fertility, and those using clarithromycin have revealed evidence of adverse effects on pregnancy outcomes and/or embryofetal development (e.g., cleft palate, delayed fetal growth). Animal models have revealed evidence of fetal mortality and lower fetal weight associated with potentially maternally toxic doses; however, these studies have failed to reveal teratogenic evidence. Amoxicillin may affect glut flora and could decrease estrogen absorption, resulting in a potential for reduced efficacy of hormonal contraception. There are no controlled data for any drug in human pregnancy.

US FDA pregnancy 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.

See references

A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother.

Excreted into human milk: Yes (amoxicillin, clarithromycin); Unknown (lansoprazole)
Excreted into animal milk: Yes (lansoprazole)

Comments:
-The American Academy of Pediatrics considers amoxicillin compatible with breastfeeding.
-The WHO considers amoxicillin compatible with breastfeeding.
-Exposed infants should be monitored for sensitization (e.g., rash), diarrhea, appetite loss, and/or somnolence.

Animal models receiving lansoprazole in breastmilk have revealed evidence of tumorigenicity in carcinogenicity studies; there is a potential risk of serious adverse reactions to the nursing infant.

The WHO recommends that breastfed infants who develop a rash should not be given subsequent doses of this drug. Alternative agents may be considered.

See references