Buster J E, Sakakini J, Killam A P, Scragg W H
Am J Obstet Gynecol. 1976 Jul 1;125(5):672-6. doi: 10.1016/0002-9378(76)90792-4.
Maternal unconjugated estriol levels were measured throughout the 28 to 41 week interval in two groups of accurately dated normal pregnancies. The first group consisted of randomly sampled pregnancies on which 285 unconjugated estriol determinations were performed. The logarithms of the mean values plotted into a positive sloping, relatively straight line which was disrupted by a plateau originating at 31 to 32 weeks and terminated at 35 weeks where there began a steep surge to a point at 36 weeks (surge point) that returned values to fit the previously established straight line. To investigate these findings in individual pregnancies, a second group of nine subjects was studied with serial unconjugated estriol determinations. In all nine of these subjects, the surge point could be identified statistically and occurred at a mean gestational age of 36.0 +/- 0.6 (1 S.D.) weeks. Data from the first group of randomly sampled pregnancies indicate that the surge point occurred around a mean gestational age of 36.0 weeks and was confirmed by data from the second group of serially sampled individual subjects showing the surge point as a statistically definable marker in normal pregnancies.
在两组精确确定孕周的正常妊娠中，在整个28至41周期间测量母体未结合雌三醇水平。第一组由随机抽样的妊娠组成，对其进行了285次未结合雌三醇测定。平均值的对数绘制成一条正斜率、相对直线的曲线，该曲线在31至32周处出现一个平台期，在35周处终止，在35周开始急剧上升至36周的一个点（激增点），此时数值回归到之前建立的直线。为了在个体妊娠中研究这些发现，对第二组9名受试者进行了连续未结合雌三醇测定。在所有这9名受试者中，激增点可以通过统计学方法确定，平均发生孕周为36.0±0.6（1个标准差）周。第一组随机抽样妊娠的数据表明，激增点发生在平均孕周36.0周左右，第二组连续抽样个体受试者的数据证实了这一点，显示激增点是正常妊娠中一个可通过统计学定义的标志物。
