Table 1.
The distribution of gestation week(GW) of preterm birth.
Table 2.
Characteristics of participants in the preterm birth group and control group.
Table 3.
Maternal health during pregnancy and risk of preterm birth.
Table 4.
Pregnancy complications and risk of preterm birth.
Table 5.
Obstetric history, family history and risk of preterm birth.
Table 6.
Risk factors for preterm birth.