3.1 Clinical characteristics of PE and control groups.
By comparatively screening the clinical data of pregnancy women (such as BMI index, age, number of pregnancy and abortion, etc.), we enrolled 1138 cases as case group and 1342 cases as control group . There is no statistical difference in the above characteristics between the two groups (P > 0.05). However, the systolic and diastolic blood pressure were higher in the case group than in the control group, and the difference was statistically significant (P <0.05); The admission pregnancy week, gestation week to terminate pregnancy and fetal birth weight were significantly lower in the case group than in the control group (P <0.05). See Table 1.