Bone Abstracts

Objective: To evaluate the BMD changes around 2 years after delivery using standard dual energy X-ray absorptiometry (DXA) of the lumbar spine and hip, peripheral quantitative computerized tomography (pQCT) of the distal tibia and radius, and quantitative ultrasound (QUS) of the oscalcis.

Methods: Consecutive patients with uncomplicated singleton pregnancies were recruited from a general obstetric clinic. Standard BMD measurements of the lumbar spine and hips were performed using DXA and volumetric BMD of the distal radius and distal tibia were also performed using pQCT techniques within 3 weeks after the index delivery, and then repeated after 21–24 months. Those that delivered preterm before 36 weeks or who had significant medical problems antenatally or postnatally were excluded.

Results: A total of 111 patients with complete data were analyzed. Uniform gains in BMD were observed between the interval assessments in the lumbar spine (L2–L4), neck of femur, as well as core and total BMD of the distal radius but not the distal tibia. The mean increase in BMD at the different sites ranged from 0.02% (distal tibia total) to 5.67% (oscalcis QUS) of the early postpartum value. The gain in general appeared to be higher in areal BMD values as measured by DXA compared to volumetric BMD values as measured by pQCT. QUS also showed a significant gain in the derived BMD value of 5.6% in the oscalcis. The correlation between the measured BMD gain from the three techniques were fair.

Conclusion: Significant gains in BMD at various bone sites were observable within 24 months after delivery, using both radiological methods (DXA and pQCT) for areal and volumetric BMD measurement as well as by QUS of the oscalcis. The uniform gain in BMD at all sites demonstrated clearly the recovery of BMD loss from pregnancy. There was good agreement between results from radiological assessment as compared to QUS.