Studies in animals with this drug have shown reproductive toxicological effects including pre and post implantation losses, decreases in viable fetuses, and visceral, skeletal and external malformations at 1.5 times the expected human exposure. The potential risk for humans is unknown.

Signs of maternal toxicity were observed with high-doses of this drug, and included reduced body weights and food consumption.

Fertility:
Studies in rats showed exaggerated pharmacological effects may be related to the compound inhibition of skeletal calcium mobilization, resulting in periparturient hypocalcemia (a bisphosphonate class effect), dystocia and early termination of the study.

The impact of variables such as time between cessation of bisphosphonate therapy to conception, the type of bisphosphonate used, and the route of administration on this risk have not been established.

AU TGA pregnancy category B3: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.

US FDA pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Use is contraindicated. (UK, AU)
Use should be avoided. (US)

AU TGA pregnancy category: B3
US FDA pregnancy category: D

Comments: This drug is not recommended in women of childbearing potential. If a patient becomes pregnant while taking or after taking this drug, the patient should be informed of the potential hazard to the fetus.

See references

Use is contraindicated. (AU,UK)
A decision should be made to discontinue breastfeeding or discontinue the drug, taking into account the importance of the drug to the mother. (US)

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

Comments: Zoledronic acid binds to bone long term and may be released over weeks to years.

See references