Demographic table comparing characteristics of women in the development and validation cohorts.

Results for continuous variables presented as mean (± standard deviation [SD]) when data normally distributed or median (interquartile range) for skewed data.*p-Values calculated using chi-squared test for categorical variables and Student's t-test or Mann-Whitney U for continuous variables.EDD, estimated date of delivery; GA, gestational age.连续变量若呈正态分布，结果以均值（±标准差(standard deviation, SD)）形式呈现；若呈偏态分布，则以中位数（四分位数间距）形式报告。* 带*标记的p值采用卡方检验计算分类变量的组间差异，采用学生t检验或曼-惠特尼U检验计算连续变量的组间差异。EDD（预估分娩日期，estimated date of delivery）；GA（胎龄，gestational age）。