title: [Secular trends of operative vaginal delivery in southern and northern China during 1993-2010].
abstract: OBJECTIVE
  To explore the secular trends of operative vaginal delivery (OVD) among nulliparous and multiparous women in southern and northern China.
  
  
  METHODS
  A population-based perinatal healthcare surveillance system has been established in 26 counties/cities in Zhejiang,Jiangsu and Hebei provinces since 1993. A total of 1 569 381 singleton pregnant women were registered during 1993-2010.Information concerning demographic characteristics and delivery mode was from surveillance records. OVD includes vacuum, forceps, assisted breech and breech extraction. Trend Chi-square test was performed to test the trends in OVD prevalence rate with the calendar years.
  
  
  RESULTS
  78 327 OVDs were identified among 1 317 771 nulliparous women and 8 702 among 251 610 multiparous women respectively. The OVD prevalence rate was 5.9% in nulliparous women and 3.5% in multiparous women. The OVD prevalence rate decreased remarkably by 92.5% from 10.6% (38 536/364 503) during 1993-1995 to 0.8% (691/84 714) during 2006-2010 in nulliparous women and by 90.0% from 5.9% (4 085/69 099) to 0.6% (116/20 280) in multiparous women. Moreover, stratified analyses consistently showed a decreasing trend in the OVD prevalence rate during the 18-year period regardless of living locations, delivery hospitals or demographic characteristics.In nulliparous women, the OVD prevalence rate decreased from 9.4% (5 271/56 163) during 1993-1995 to 1.4% (157/11 030) during 2006-2010 in southern urban area, from 11.8% (32 361/273 274) to 1.4% (402/29 069) in southern rural area and from 2.6% (904/35 066) to 0.3% (132/44 615) in northern rural area, and decreased from 8.6% (5 506/63 796) to 1.3% (208/16 408) at provincial hospitals, from 10.8% (13 659/126 529) to 0.7% (381/55 100) at county hospitals and from 12.1% (19 054/157 439) to 0.8% (100/12 959) at township hospitals. And similar results were further observed in different subgroups stratified by demographic characteristics.In multiparous women, a decreasing trend in OVD prevalence rate during the 18-year period was re-identified in various subgroups.
  
  
  CONCLUSIONS
  The OVD prevalence rate in both nulliparous and multiparous women dramatically decreased in China during 1993-2010 and ranked the lowest in the world by 2010. Thus the relevant government departments should be prepared for the expected rebound in the occurrence of OVD given the national health policies of promoting vaginal deliveries.
authors.affiliation: Institute of Reproductive & Child Health/ Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology & Biostatistics, School of Public Health, Peking University, Beijing 100191, China.
authors.forename: Yubo
authors.initials: Y
authors.lastname: Zhou
authors.forename: Hongtian
authors.initials: H
authors.lastname: Li
authors.affiliation: Email: shzhuliping@163.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Zhu
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Li
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Email: liujm@pku.edu.cn.
authors.forename: Jianmeng
authors.initials: J
authors.lastname: Liu
mesh_terms: D002681:China; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D010298:Parity; D011247:Pregnancy; D015995:Prevalence