O'Keeffe D F, Garite T J, Elliott J P, Burns P E
Am J Obstet Gynecol. 1985 Feb 1;151(3):309-12. doi: 10.1016/0002-9378(85)90292-3.
The management of patients with preterm premature rupture of the membranes is often influenced by the ultrasound measurement of biparietal diameter. The cephalic index has been used in pregnancies with intact membranes to predict the presence of an abnormal biparietal diameter that may be unreliable in estimating gestational age. This study analyzed 100 patients with rupture of the membranes between the beginning of gestation week 28 and the end of week 34. The cephalic index was found to be abnormal 45% of the time; all were in the brachiocephalic range. The biparietal diameter was affected by presentation and presence or absence of amniotic fluid (p less than 0.05). Use of the biparietal diameter was found to be unreliable in estimating gestational age with preterm premature rupture of the membranes. Use of the cephalic index did not enable prediction of which biparietal diameters would be abnormal; therefore use of the biparietal diameter or the cephalic index in preterm premature rupture of the membranes is not recommended. The use of the head circumference, abdominal circumference, and femur measurements may be a better way of predicting gestational age in this select population.
胎膜早破患者的管理常常受到双顶径超声测量结果的影响。头围指数已被用于胎膜完整的妊娠中，以预测可能在估计孕周时不可靠的异常双顶径的存在。本研究分析了100例在妊娠第28周开始至第34周结束之间发生胎膜破裂的患者。发现头围指数有45%的时间异常；所有异常均在短头范围内。双顶径受胎位以及羊水的有无影响（P<0.05）。发现在胎膜早破的情况下，使用双顶径来估计孕周是不可靠的。使用头围指数无法预测哪些双顶径会异常；因此，不建议在胎膜早破时使用双顶径或头围指数。对于这一特定人群，使用头围、腹围和股骨测量值可能是预测孕周的更好方法。
