Animal studies have failed to reveal evidence of embryotoxicity or teratogenicity when this drug was administered prior to and during mating, throughout pregnancy, and until weaning at doses up to 3 times the maximum recommended human dose. Observational studies have revealed evidence of cardiovascular malformations after exposure to this drug in early pregnancy. There are no controlled data in human pregnancy.

AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

This drug should be used during pregnancy only if clearly needed.

AU TGA pregnancy category: A
US FDA pregnancy category: Not assigned.

Risk Summary: There are no adequate and well-controlled data available on use of this drug in pregnant women to inform of a drug-related risk.

Comment:
-Congenital syphilis prophylaxis: Reports suggest that this drug may not attain adequate fetal drug concentrations to prevent congenital syphilis. Infants born to patients who were treated with oral formulations of this drug for early syphilis should be given an appropriate penicillin regimen.

See references

The WHO states that breastfed infants should be monitored for gastrointestinal disturbances (e.g., diarrhea, thrush). If adverse events occur, breastfeeding should continue, and an alternative treatment should be selected (if necessary).

In a small trial (N=2), patients given 500 mg orally had milk levels of 1, 1.2, and 1.1 mg/L at 2, 4, and 6 hours after dosing, respectively. In a trial of patients (N=15) given 500 mg IV, breastmilk levels 2 hours after dosing were 2.5 mg/L.

There are case reports suggesting that a higher risk of IHPS may be associated with maternal exposure within 7 weeks of delivery.

Caution is recommended.

Excreted into human milk: Yes

Comments:
-The WHO considers this drug compatible with breastfeeding.
-The American Academy of Pediatrics (AAP) considers this drug compatible with breastfeeding.
-Some experts consider this drug compatible with breastfeeding; breastfed infants should be monitored for irritability, infantile hypertrophic pyloric stenosis (IHPS) and effects on the gastrointestinal flora (e.g., diarrhea, candidiasis [diaper rash, thrush]).

See references