[Post-pregnancy osteoporosis. A case report]

Pregnancy-related fractures: a retrospective study of a French cohort of 52 patients and review of the literature

A retrospective, multicentre study involving 52 patients was carried out to define the causes and characteristics of pregnancy-related osteoporosis. The mean number of vertebral fractures occurring during the last trimester of pregnancy or at the time of delivery was 3.8. This is often promoted by risk factors before or during pregnancy.

INTRODUCTION

In order to define the causes or predisposing factors of pregnancy-related osteoporosis and its clinical, radiological and bone density characteristics, laboratory findings, course and outcome, we carried out a retrospective multicentre study.

METHODS

The records of 52 women hospitalised over the last 10 years in the rheumatology departments of six French university hospitals and with a diagnosis of pregnancy-related osteoporosis were examined.

RESULTS

The patients' mean age at time of fracture was 32.1 years. In 10 patients, the fractures had occurred during the last trimester of pregnancy, and in 36 at the time of delivery or during the first 2 months post-partum. The mean number of vertebral fractures was 3.8 ± 2.0. Thirty three of the 52 patients had a risk factor of low bone mass before pregnancy. Twelve had disorders or treatments (heparin) that might promote osteoporosis during pregnancy, while 14 had no trigger factors before or during pregnancy. Overall, phosphate and calcium levels were normal, except for hyperphosphoraemia in lactating women (90%). On DXA scan, osteoporosis predominated in the trabecular bone (spinal T-score - 3.4, hip T-score - 2). Only 10 patients had a repeat fracture, and the increase in bone mineral density during follow-up was considerable, and improved by bisphosphonates (annual gain + 10% in the spine) or teriparatide (+ 15%).

CONCLUSIONS

Pregnancy-related osteoporosis gives rise to multiple vertebral fractures. It is often promoted by risk factors before or during pregnancy. Its mechanism is still unknown. Treatment with bisphosphonates or teriparatide appears to improve the recovery of bone mineral density.

Ostéoporose gravidique

INTRODUCTION

Pregnancy-associated osteoporosis is a rare disorder and its pathophysiology remains unknown. EXEGISIS: We report a case of pregnancy-associated osteoporosis in a 27-year-old primiparous patient, revealed by acute lumbar pain and a right costal pain during the last month of pregnancy. The standard radiographs showed multiple vertebral compression fracture and a 10th rib fracture. The diagnosis of osteoporosis was established by osteodensitometry. Diagnostic work-up excluded a secondary osteoporosis, and the outcome was favourable with an increase of bone mineral density after 2 years of treatment with calcium, vitamin D and alendronate 10 mg/j.

CONCLUSION

Although rare, diagnosis of pregnancy-associated osteoporosis should be suspected when thoracic or lumbar spine pain occur during pregnancy or in the post-partum period as it can lead to vertebral or peripheral fractures.