Crude and adjusted OR for emotional distress and early and late preterm birth.

*cases with covariates missing are excluded.†adjusted for maternal age, educational level, marital status, smoking, pre-pregnancy body mass index, late medical risk, history of spontaneous abortion, and neonate gender.‡emotional distress at 17 and 30 weeks are dichotomized variables, mean score ≥2 = 1.§compared to no emotional distress at 30 weeks.||OR not calculated because the exposure was measured simultaneously with the outcome variable.

* 存在协变量缺失的病例已被排除。
† 校正因素包括产妇年龄、受教育程度、婚姻状况、吸烟情况、孕前体重指数、晚期妊娠医疗风险、自然流产史及新生儿性别。
‡ 孕17周与孕30周时的情绪困扰为二分类变量，平均得分≥2时赋值为1。
§ 以孕30周无情绪困扰者作为参照组。
|| 由于暴露因素与结局变量同步测量，故未计算比值比（Odds Ratio，OR）。