<p>Pregnancy category C. Overdoses of vitamin D have shown teratogenic effects in pregnant animals. Alendronic Acid &amp; Vitamin D3 (Colecalciferol) should be used during pregnancy only if the potential benefit justifies the potential risk to the mother and fetus. Cholecalciferol and some of its active metabolites pass into breast milk. It is not known whether alendronate is excreted in human milk. Caution should be exercised when administered to lactating women.</p>