Patients with endometriosis and other diseases that would affect pregnancy were excluded [2 (link)].
Pregnancy: positive pregnancy test and uterine B-ultrasound revealed the gestational sac in the uterus
The categorization was as follows: abortion: less than 28 weeks of pregnancy loss; premature delivery: delivery from 28 weeks of pregnancy to less than 37 weeks; full-term delivery: pregnancy greater than 37 weeks of delivery
Postpartum hemorrhage: the blood loss exceeded 500 mL within 24 h after delivery and exceeded 1000 mL during the cesarean section