Pregnancy-associated osteoporosis: report of two cases with long-term bone density follow-up.

Pregnancy-associated osteoporosis is a rare and poorly characterized clinical entity. We describe two women, aged 28 and 31 yr, who developed vertebral osteopaenia with non-traumatic compression fractures within a few months after delivery. In both women secondary causes of osteoporosis were excluded and routine laboratory data including indices of calcium metabolism were normal. In one patient (Patient 1) spontaneous secretion of IL-1 by cultured blood monocytes was elevated 6 months after delivery and a bone biopsy revealed histomorphometric indices consistent with accelerated bone remodelling. BMD was measured by quantitative computed tomography (QCT) and/or dual energy X-ray absorptiometry (DXA). In Patient 1, BMD, measured with QCT, 6 months after delivery was 3.32 Z-score units below the predicted value for age and sex-matched subjects. At that time treatment (phosphate followed by sodium etidronate) was instituted, and QCT measurements obtained 24 and 30 months after delivery revealed a BMD of -2.98 and -2.67 Z-score units, respectively. The treatment was discontinued just before she became pregnant again, and 3 months after the second delivery QCT showed a BMD of -3.06 Z-score units. Further BMD assessments were obtained with DXA at 15 and 18 months after the second delivery, and the BMD values were -1.41 and -1.08, respectively. In Patient 2, spine BMD, measured with QCT, 4 and 10 months after delivery were -1.68 and -1.59 Z-score units, respectively. At 10, 16 and 22 months after delivery, BMD was assessed with DXA. The initial measurement with this technique disclosed a BMD of 0.52 Z-score units.(ABSTRACT TRUNCATED AT 250 WORDS)