Table 1

Baseline and obstetric characteristics of the study subjects (n=164 107)

Characteristic2020 (n=24 312)2014–2019 (n=139 795)
Maternal age, years—%
 ≥35.018.816.1
 25.0~34.978.680.0
 <25.02.63.9
 Insurance—%73.471.3
 Married—%99.299.2
 Nulliparity—%73.974.8
BMI at first prenatal visit—%
 ≥30.01.81.5
 25.0–29.912.511.9
 20.0–24.957.357.8
 <20.028.428.8
 Education—years (mean±SD)15.3±2.814.9±2.6
 Assisted conception—%2.93.2
 DM and GDM—%11.312.3
 Hypertensive disorders—%5.85.4
 ICP—%1.21.0
Gestational age at delivery—%
 <32 GW0.50.7
 32–36 GW4.74.7
 ≥37 GW94.894.6
 Stillbirth—%0.20.2
Birth weight—%
 Large for gestational age4.74.5
 Average for gestational age92.492.3
 Small for gestational age2.93.2
Delivery mode—%
 Spontaneous delivery54.560.6
 Assisted vaginal delivery1.51.3
 Caesarean delivery44.038.1
  • BMI, body mass index; DM, pregestational diabetes; GDM, gestational diabetes; GW, gestational week; ICP, intrahepatic cholestasis of pregnancy.