To William W K, Wong Margaret W N, Leung Tsin-Wah
Department of Obstetrics and Gynecology, United Christian Hospital, Hong Kong, China.
Acta Obstet Gynecol Scand. 2003 Sep;82(9):820-7. doi: 10.1034/j.1600-0412.2003.00227.x.
The study aims to verify whether a progressive fall in bone mineral density (BMD) values can be demonstrated using quantitative ultrasound measurements of the os calcis. The BMD change during the pregnancy was then correlated with other maternal and pregnancy characteristics to identify any high-risk factors for bone loss in pregnancy.
Consecutive patients were recruited from a low-risk obstetric clinic over a period of 9 months. BMD measurements were performed at the os calcis before 18 weeks, between 28 and 32 weeks, and at 36-38 weeks using a Hologic Sahara Clinical Bone Sonometer system. A computer-derived BMD value was obtained with each measurement. Body fat composition was also measured using a Tanita 501 bioimpedance assay system.
In a cohort of 780 patients, a mean fall in BMD of 0.040 g/cm2 was demonstrable across the trimesters. The difference in BMD across the three serial measurements was highly significant (p < 0.001). Univariate analysis showed that those with a low initial BMD, glucose intolerance and high body fat accumulation weight gain during the pregnancy had lower BMD loss, while gestational hypertension and obesity had no impact on the degree of BMD loss. Entering these parameters in a logistic regression analysis showed that the impact of glucose intolerance was lost, but that the other factors remained significant. A linear regression model of quantitative variables showed that only fat accumulation (p = 0.03) and early pregnancy BMD values (p < 0.001) remained significant factors associated with BMD loss.
A gradual fall in BMD was demonstrable using ultrasound measurement of the os calcis from early to late pregnancy. Of the various parameters identified as significant factors affecting BMD loss in pregnancy, a low initial BMD in early pregnancy and high body fat accumulation during pregnancy appeared to be related to lower BMD loss.
本研究旨在验证通过跟骨定量超声测量是否能证明骨密度（BMD）值呈渐进性下降。然后将孕期骨密度变化与其他母体及妊娠特征进行关联，以确定孕期骨质流失的任何高危因素。
在9个月的时间里，从一家低风险产科诊所招募连续的患者。使用Hologic Sahara临床骨超声仪系统在孕18周前、28至32周之间以及36 - 38周时对跟骨进行骨密度测量。每次测量均获得计算机得出的骨密度值。还使用Tanita 501生物电阻抗分析系统测量体脂成分。
在780名患者的队列中，整个孕期骨密度平均下降0.040 g/cm²。三次连续测量的骨密度差异具有高度显著性（p < 0.001）。单因素分析表明，初始骨密度低、糖耐量异常以及孕期体脂积累体重增加者骨密度损失较低，而妊娠期高血压和肥胖对骨密度损失程度无影响。将这些参数纳入逻辑回归分析显示，糖耐量异常的影响消失，但其他因素仍然显著。定量变量的线性回归模型显示，只有脂肪积累（p = 0.03）和孕早期骨密度值（p < 0.001）仍然是与骨密度损失相关的显著因素。
通过超声测量跟骨可证明从孕早期到孕晚期骨密度逐渐下降。在确定为影响孕期骨密度损失的重要因素的各种参数中，孕早期初始骨密度低和孕期体脂积累高似乎与较低的骨密度损失有关。
