Animal studies have reported evidence of interference with fertility, gestation, and fetal development. Cardiac and other anomalies, including Ebstein's anomaly, have been reported in humans. Newborns exposed throughout pregnancy may have signs/symptoms of lithium toxicity, but they were usually self-limiting and resolved within 1 to 2 weeks.

In vitro studies in male animals have reported evidence of metabolism of the testis; human males have reported evidence of spermatozoa metabolism.

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

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

Risk Summary: This drug may cause fetal harm when given during pregnancy.

Comments:
-Use of adequate methods of contraception should be encouraged.
-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.
-If used during pregnancy, serum lithium levels should be closely monitored and prenatal diagnosis of malformations should be conducted. Use should be discontinued shortly before delivery and restarted a few days postpartum.
-After birth, the newborn should be monitored for signs/symptoms of lithium toxicity, including thyroid function.

See references

Excretion of this drug into breastmilk is highly variable. Limited data reported breast milk levels of 0.12 to 0.7 mEq (approximately 40% to 45% of maternal plasma levels) and measured infant plasma levels that were approximately 30% to 40% of maternal plasma levels. There have been reports of breastfed infants who have shown signs/symptoms associated with lithium toxicity (e.g., hypertonia, hypothermia, cyanosis, and ECG changes); this may occur more frequently in infants with elimination impairments (e.g., dehydration) or in newborn/premature infants.

Use is contraindicated.
-Some experts recommend: 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

Comments:
-Some experts recommend bottle feeding due to the risk of lithium toxicity.
-If breastfeeding is continued, monitoring of infant serum lithium, serum creatinine, blood urea nitrogen levels, and thyroid function are recommended. Breastfeeding should be discontinued if breastfed infants develop lithium toxicity.

See references