Animal studies have failed to reveal evidence of fetal harm. This drug crosses the placenta. No positive evidence of adverse effects on the fetus observed during human use of penicillins; however, 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 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.

This drug should be used during pregnancy only if clearly needed; it has been used without apparent harmful effects. Caution is recommended.

AU TGA pregnancy category: A
US FDA pregnancy category: B

See references

According to limited data, single maternal doses of 1320 mg produce low levels in breast milk.

In 16 women, milk drug levels were measured after a single 1320 mg oral dose. In 7 women with mastitis, peak milk levels averaged 0.72 mg/L in the breast with mastitis and 0.58 mg/L in the unaffected breast; peak levels occurred 2.6 to 2.7 hours after dosing. In 4 controls (women without mastitis), peak milk levels averaged 0.3 mg/L at 5.4 hours after dosing. Differences in mastitic milk levels and control milk levels were statistically significantly from nonmastitic milk levels in the women with mastitis in the opposite breast. The average milk level and AUC were greater in the women with mastitis (not statistically significant). According to author estimation, an exclusively breastfed infant would receive about 50 mcg/kg/day (range: 20 to 90 mcg/kg/day).

Nursing mothers were given a single 1320 mg oral dose. At 2 hours after nursing, urine drug level was measured in 2 of the breastfed infants; urine level was undetectable in 1 infant and 520 mcg/L in the other infant.

In 1 study, 12 infants were breastfed during maternal use of this drug. No effects were observed in 7 infants (appeared normal), looser stools than normal occurred in 3 infants, and a rash developed on the buttocks of 1 infant on the last day of therapy; such effects were possibly related to penicillin V in milk, but there was no control group. Stains of blood were seen in the stool of 1 infant, but this had occurred one time before the mother used this drug.

Use is considered acceptable; caution is recommended.
-According to some authorities, this drug should not be used unless the benefit outweighs the risk.

Excreted into human milk: Yes

Comments:
-Low levels in milk are not expected to cause harmful effects in the nursing infant.
-Disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) reported occasionally with penicillins, but such effects have not been adequately evaluated; possibility of allergy/sensitization should be considered.

See references