Tadmor O P, Achiron R, Rabinowiz R, Aboulafia Y, Mashiach S, Diamant Y Z
Department of Obstetrics and Gynecology, Shaarei Zedek Medical Center, Jerusalem, Israel.
J Reprod Med. 1994 Jun;39(6):459-62.
First-trimester spontaneous abortions have been predicted from alterations in the gestational sac size and embryonic heart rate. To evaluate which parameter or combination of parameters has the greatest predictive value, a prospective study was carried out during the first trimester of pregnancy. Pregnancy sac size, crown-rump length and heart rate were measured in 603 embryos, of which 580 continued beyond 13 weeks' gestation and 23 ended in first-trimester spontaneous abortions. Based on the continuing pregnancies, we constructed nomograms relating the ratio of mean sac diameter to crown-rump length (S/CR) to gestational age (last menstrual period [LMP]), to crown-rump length (CRL) and to embryonic heart rate (EHR). The S/CR ratios of the 23 embryos that spontaneously aborted in the first trimester were plotted on these nomograms to determine the significance of values falling outside the 95% confidence limits. Plotting the S/CR ratios of the aborted fetuses on the S/CR versus LMP nomogram gave a sensitivity of 78.3%, a specificity of 97.8% and a false-positive rate of 2.2%. The same population was evaluated for abortion risk using EHR nomograms, giving a sensitivity of 65.2%, specificity of 98.2% and false-positive rate of 1.8%. Our findings suggest that S/CR measurement in early pregnancy may be a simple and reliable method of predicting first-trimester abortions.
早孕期自然流产可通过妊娠囊大小和胚胎心率的改变来预测。为评估哪个参数或参数组合具有最大的预测价值，在妊娠早期进行了一项前瞻性研究。对603个胚胎测量了妊娠囊大小、头臀长度和心率，其中580个胚胎妊娠持续超过13周，23个以早孕期自然流产告终。基于持续妊娠的情况，我们构建了列线图，将平均囊直径与头臀长度之比（S/CR）与孕周（末次月经日期[LMP]）、头臀长度（CRL）和胚胎心率（EHR）相关联。将23例在早孕期自然流产的胚胎的S/CR比值绘制在这些列线图上，以确定落在95%置信区间之外的值的意义。将流产胎儿的S/CR比值绘制在S/CR与LMP列线图上，敏感性为78.3%，特异性为97.8%，假阳性率为2.2%。使用EHR列线图对同一人群进行流产风险评估，敏感性为65.2%，特异性为98.2%，假阳性率为1.8%。我们的研究结果表明，孕早期测量S/CR可能是预测早孕期流产的一种简单可靠的方法。
