[Osteoporosis during pregnancy. 4 cases].

Osteoporosis of pregnancy is an infrequent condition of unclear pathogenesis. We report four new cases. Mean age of patients was 28 years; diffuse bone loss was seen on pre-pregnancy roentgenograms in two patients. Two patients were primiparas. In all four cases, acute spinal pain led to the discovery of vertebral crush fractures and diffuse osteopenia predominating in the spine and pelvis. Urinary calcium was low in one case. Our cases and a review of the literature demonstrate that diffuse osteopenia exists prior to the pregnancy and becomes symptomatic during childbearing as a result of additional mechanical stresses with or without concomitant vitamin D deficiency and/or heparin therapy.