Animal studies have revealed evidence of embryofetal toxicity and teratogenicity at maternotoxic doses. In rats, this drug resulted in reduced placental weights and signs of fetal toxicity (including reduced fetal weight, impaired fetal ossification) at the maternotoxic dose of 10 mg/kg/day (corresponding to AUC[unbound] of 19 times that in humans); at 30 mg/kg/day (corresponding to AUC[unbound] of about 25 times that in humans), increased incidence of visceral and skeletal variations (slight edema, shortened umbilical cord, slightly enlarged fontanelle) was observed, and 1 fetus showed complex malformations (including a rare double aortic arch). The doses free of any findings (low dose in rats, high dose in rabbits) provide safety margins of 10 to 13 times for the AUC(unbound) expected in humans. Rats exposed to this drug during pregnancy and lactation showed increased pup mortality and other adverse effects(lower pup weight, delayed pinna unfolding) at about 4 times the AUC(unbound) expected in humans. Placental transfer of this drug and/or its metabolites has been shown in rats. There are no controlled data in human pregnancy.

AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.

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 not be used during pregnancy unless the benefit outweighs the risk to the fetus.
-According to some authorities: Use is not recommended unless clearly needed.

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

Risk summary: No data available on use of this drug during pregnancy to inform a drug-related risk.

Comments (according to some authorities):
-If the patient becomes pregnant while taking this drug, the patient should be apprised of the potential harm to the fetus.
-Patients of childbearing potential should be advised to use effective contraception during therapy.

See references

Breastfeeding is not recommended during use of this drug and for 1 day after treatment.
-According to some authorities: Breastfeeding should be discontinued if use of this drug is considered essential.
-According to some authorities: A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother and the benefit of breastfeeding for the child.

Excreted into human milk: Unknown
Excreted into animal milk: Yes

Comments:
-No information is available on the use of this drug during breastfeeding; because this drug is highly bound to plasma proteins, amounts in milk are likely to be low.
-The effects in the nursing infant are unknown; there is a potential risk from exposure to this drug.

See references