Evidence shows that pregnancy and lactation lead to the decrease of bone mineral density (BMD), which is related to mobilization of skeletal calcium. Numeorous mechanisms are involved in maternal adaptation to the increased demand for calcium. BMD has been proved to return to the baseline level after weaning. Pregnancies and long or repeated periods of feeding do not seem to determine the diagnosis of osteoporosis in later life. In fact, women with multiple pregnancies have been shown to have the same or higher BMD and lower fracture risk compared with nulliparous women. Pregnancy and lactation-associated osteoporosis (PLO) is a rare disease entity. It manifests itself as low back pain, and often leads to a number of vertebral compression fractures and, therefore, to potentially serious health consequences.