title: [Incidence and risk factors for postpartum hemorrhage in Liuyang, China].
abstract: OBJECTIVE
  To investigate the incidence and risk factors of postpartum hemorrhage in Liuyang City, Hunan Province.
  
  
  METHODS
  This was a nested case-control study. A total of 14 townships were randomly selected by cluster random sampling method from 37 townships in Liuyang City, Hunan Province. All women who got pregnant and childbirth from January 2010 to December 2011 in the above 14 townships were selected and followed up at first-trimester, second trimester, third trimester and each delivery period. Data were collected directly from maternal care manuals and the clinical records from the subjects' delivery hospitals. These whose postpartum bleeding was more than 500 mL were selected as cases, and the same amounts of normal maternal in the same cohort study whose postpartum bleeding was less than 500 mL were selected as controls. χ2 test and unconditional logistic regression analysis were applied to identify the determinants.
  
  
  RESULTS
  A total of 5 933 women were included in our study. The incidence of postpartum hemorrhage was 2.22%. Unconditional logistic regression analysis showed that the risk factors for postpartum hemorrhage mainly included anemia (OR=3.940, 95% CI: 2.100-7.389), scarred uterus (OR=2.730, 95% CI: 1.198-6.220), placenta previa (OR=10.665, 95% CI: 1.142-99.566), placental factors (OR=4.332, 95% CI: 1.004-18.692), and prolonged pregnancy (OR=5.899, 95% CI: 2.602-13.376).
  
  
  CONCLUSIONS
  Postpartum hemorrhage is caused by complicated factors. Comprehensive measures should be taken to reduce postpartum hemorrhage.
authors.affiliation: School of Public Health, Central South University, Changsha 410078,China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Wang
authors.forename: Hongzhuan
authors.initials: H
authors.lastname: Tan
authors.forename: Shujin
authors.initials: S
authors.lastname: Zhou
authors.forename: Yue
authors.initials: Y
authors.lastname: He
authors.forename: Lin
authors.initials: L
authors.lastname: Shen
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Hu
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
mesh_terms: D016022:Case-Control Studies; D002681:China; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D015994:Incidence; D006473:Postpartum Hemorrhage / Q000453:epidemiology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012307:Risk Factors