Wilcox A J, Treloar A E, Sandler D P
Am J Epidemiol. 1981 Oct;114(4):548-53. doi: 10.1093/oxfordjournals.aje.a113220.
A prospective study of menstrual cycles and reproductive outcomes has been in progress since 1935. Data from this study are used to describe the risk of spontaneous abortion in two time periods 26 years apart. Out of the total of 3889 women who have enrolled in this study, two cohorts of women are selected for analysis: cohort one consists of 2070 university students who entered the study in 1935-1944, and cohort two consists of 1375 students a generation later, 1961-1970. Cohort one has contributed 2408 pregnancies, and cohort two, 1493 pregnancies. Overall spontaneous abortion risk for the two cohorts is 16.9% and 13.1%, respectively. However age-specific risks of spontaneous abortion do not differ for the two groups, nor is there a difference in the gestational duration of spontaneously aborted pregnancies.
自1935年以来一直在进行一项关于月经周期和生殖结局的前瞻性研究。该研究的数据用于描述相隔26年的两个时间段内自然流产的风险。在参与这项研究的总共3889名女性中，选取了两组女性进行分析：第一组由1935年至1944年进入该研究的2070名大学生组成，第二组由一代之后1961年至1970年的1375名学生组成。第一组有2408次妊娠，第二组有1493次妊娠。两组的总体自然流产风险分别为16.9%和13.1%。然而，两组的年龄特异性自然流产风险没有差异，自然流产妊娠的孕周也没有差异。
