title: [A population based study on incidence and determinants of preterm birth in Liuyang Hunan].
abstract: OBJECTIVE
  To describe the incidence and to discuss the risk factors of premature birth in rural areas of Liuyang.
  
  
  METHODS
  We collected subjects from villages and towns in Liuyang through cluster sampling method. Before enrolling in this cohort, all of them had established health records from January 2010 to December 2011. We followed up the early, middle and late stages of pregnancy until delivery, and collected medical records and maternal health care manual of this cohort as our data materials. We explored the main influence factors of premature delivery by χ2 test and unconditional logistic regression analysis for single factor and multivariate analysis.
  
  
  RESULTS
  Among 6270 women who enrolled in our cohort, 259 were diagnosed as premature birth. The incidence (4.13%) was lower than the national average level. Non-conditional logistic regression analysis showed that the risk factors of premature birth were as follows: OR of placental abruption was 7.678 (95% CI: 2.249-26.215), that of premature rupture of fetal membranes (PROM) was 5.177 (95% CI: 3.945-6.793), that of uterine abnormal and deformity was 2.675 (95% CI: 1.007-7.107), that of placenta anomaly was 2.633 (95% CI: 1.666-4.162), that of hypertension in pregnancy was 2.172 (95% CI: 1.044-4.521), that of pregnancy complications was 1.806 (95% CI: 1.033-3.157), that of male fetus was 1.429 (95% CI: 1.086-1.881). Protective factors of preterm birth were too frequent prenatal examination (OR=0.502, 95% CI: 1.033-3.157) and single pregnancy (OR=0.155, 95% CI: 0.075-0.319).
  
  
  CONCLUSIONS
  Preterm delivery is caused by complicated factors, such as placental abruption, PROM and male fetus. Comprehensive measures should be taken to reduce preterm birth.
authors: Department of Epidemiology and Health Statistics, Central South University, Changsha, China.
authors: Yawei
authors: Y
authors: Guo
authors: Hongzhuan
authors: H
authors: Tan
authors: Shujin
authors: S
authors: Zhou
authors: Meiling
authors: M
authors: Luo
authors: Shaya
authors: S
authors: Wang
authors: Chang
authors: C
authors: Cai
authors: Li
authors: L
authors: Hu
authors: Yue
authors: Y
authors: He
authors: Yi
authors: Y
authors: Liu
authors: Lin
authors: L
authors: Shen
authors: Shiwu
authors: S
authors: Wen
mesh_terms: D000037:Abruptio Placentae / Q000209:etiology; D000328:Adult; D002681:China / Q000453:epidemiology; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000209:etiology; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D012424:Rural Population; D012494:Sampling Studies; D055815:Young Adult