Does treatment with bisphosphonates endanger the human pregnancy?

Bisphosphonates are clinically used in the treatment of various bone diseases including corticosteroid-induced osteoporosis, hypercalcemia associated with malignancy, and osteogenesis imperfecta. They are therefore often used in women of childbearing age, but little is known about their possible effects on the human embryo and fetus. Animal studies have revealed unfavourable effects of bisphosphonate treatment on the fetus, mainly in the skeleton. Since bisphosphonates are retained for a long time in the human skeleton, concerns have been raised that even pre-pregnancy administration of bisphosphonates may result in embryofetal exposure and alter fetal bone modelling. To obtain current information on the risks and safety of bisphosphonate use in pregnancy, we performed a systematic search of the Medline and Embase databases, from 1950 and 1974, respectively, to September 2008. Fifty-one cases of exposure to bisphosphonates before or during pregnancy were identified; none of them described any skeletal abnormalities or other congenital malformations in the infants. The bisphosphonates used were alendronate (32 cases), pamidronate (11), etidronate (5), risedronate (2), and zoledronic acid (1). Although in theory bisphosphonates may affect bone modelling and development in the fetus, the 51 cases reported to date did not detect such pathology.