title: [Association between pregnancy-induced hypertension, cesarean delivery and perinatal mortality: a prospective study].
abstract: OBJECTIVE
  To examine the relationship between pregnancy-induced hypertension (PIH) and risks of perinatal mortality.
  
  
  METHODS
  A population-based, retrospective cohort study was conducted based on 134 858 women registered in a perinatal health care surveillance system and delivered singleton births between 1995 to 2000 in Zhejiang province, China. Multivariate logistic regression models were employed to estimate the relative risk (OR) and 95%CI.
  
  
  RESULTS
  The perinatal mortality rate (95%CI) was 7.6 per thousand (7.1 - 8.1) in normotensive women and 9.2 per thousand (7.7 - 10.8) in PIH women. The cesarean delivery rate was 45.7% in normotensive women and 55.7% in groups with PIH. When compared with the normotensive women, the unadjusted OR (95%CI) for perinatal mortality was 1.21(1.01 - 1.46) in groups with PIH; 0.97 (0.77 - 1.22) in groups with mild PIH, 1.73 (1.26 - 2.37) in groups with moderate PIH, and 2.01 (1.18 - 3.43) in groups with severe PIH; 0.99 (0.77 - 1.26) in groups with PIH developed before delivery, 1.39 (1.05 - 1.84) in groups with PIH developed in second trimester, and 2.69 (1.54 - 4.69) in groups with PIH developed in third trimester. After controlling for maternal age, occupation, educational attainment, parity, times of prenatal visit, infant's sex, pregnancy complications and cesarean delivery, the OR (95%CI) for perinatal mortality was 1.09 (0.90 - 1.31) in women with PIH when compared with the normotensive groups. The adjusted OR for perinatal mortality was 0.81 (0.64 - 1.02) in groups with mild PIH, 1.94 (1.41 - 2.67) in groups with moderate PIH, and 3.32 (1.92 - 5.75) in groups with severe PIH; 0.82 (0.63 - 1.05) in groups with PIH developed before delivery, 1.51 (1.14 - 2.00) in groups with PIH in second trimester, and 2.67 (1.52 - 4.70) in groups with PIH in third trimester.
  
  
  CONCLUSIONS
  Moderate and severe PIH early developed during pregnancy could increase the risk of perinatal mortality, while cesarean delivery could decrease the risks in women with PIH.
authors.affiliation: Institute of Reproductive and Child Health, Peking University, Beijing 100191, China.
authors.forename: Rong-wei
authors.initials: RW
authors.lastname: Ye
authors.forename: Ying-hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Rui
authors.initials: R
authors.lastname: Ma
authors.forename: Ai-guo
authors.initials: AG
authors.lastname: Ren
authors.forename: Jian-meng
authors.initials: JM
authors.lastname: Liu
mesh_terms: D002585:Cesarean Section / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced; D016015:Logistic Models; D015999:Multivariate Analysis; D016017:Odds Ratio; D054238:Perinatal Mortality; D011247:Pregnancy; D011256:Pregnancy Outcome; D011264:Pregnancy Trimesters; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index