title: Contemporary second stage labor patterns in Taiwanese women with normal neonatal outcomes.
abstract: OBJECTIVE
  To compare the duration of second stage labor among modern Taiwanese women who achieved vaginal delivery without adverse neonatal outcomes and women who delivered during the early 1990 s.
  
  
  METHODS
  Data were collected from women who underwent spontaneous labor and vaginally delivered cephalic singleton fetuses with normal neonatal outcomes at the Taipei Chang Gung Memorial Hospital, Taipei, Taiwan from 1991-1995 (Cohort 1, n = 10,721) and 2010-2014 (Cohort 2, n = 3734). We calculated the median duration and 95th percentiles of second stage labor. The women were stratified according to analgesia and parity. Multiple linear regression analysis was used to determine the association between the maternal/pregnancy characteristics and second stage labor duration.
  
  
  RESULTS
  The median second stage labor duration was significantly longer for Cohort 2 than for Cohort 1. For nulliparous women, the 95th percentile second stage labor thresholds were 255 minutes and 152 minutes (Cohort 2) and 165 minutes and 107 minutes (Cohort 1) for women with and without epidural analgesia, respectively. For multiparous women, the 95th percentile second stage labor thresholds were 136 minutes and 43 minutes (Cohort 2) and 125 minutes and 39 minutes (Cohort 1) for women with and without epidural analgesia, respectively. Birth weight, maternal age at delivery, and time period (2010-2014 vs. 1991-1995) were significant factors associated with the duration of second stage labor.
  
  
  CONCLUSIONS
  Modern Taiwanese women who achieved vaginal delivery without adverse neonatal outcomes experienced longer second stage labors than women 25 years ago. The 95th percentile thresholds differed between nulliparous and multiparous women with and without epidural analgesia.
authors.affiliation: Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan. Electronic address: thh20@cgmh.org.tw.
authors.forename: Tai-Ho
authors.initials: TH
authors.lastname: Hung
authors.affiliation: Department of Physical Medicine and Rehabilitation, Cheng Hsin Rehabilitation Medical Center, Taipei, Taiwan.
authors.forename: Szu-Fu
authors.initials: SF
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Liang-Ming
authors.initials: LM
authors.lastname: Lo
authors.affiliation: Department of Obstetrics and Gynecology, Taipei Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: T'sang-T'ang
authors.initials: TT
authors.lastname: Hsieh
mesh_terms: D000328:Adult; D015360:Analgesia, Epidural / Q000009:adverse effects / Q000379:methods*; D000773:Anesthesia, Obstetrical / Q000379:methods; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects / Q000379:methods*; D003906:Developing Countries; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007748:Labor Stage, Second / Q000502:physiology*; D016014:Linear Models; D008423:Maternal Age; D015999:Multivariate Analysis; D009321:Natural Childbirth / Q000379:methods*; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D013624:Taiwan; D013997:Time Factors; D055815:Young Adult
keywords: epidural analgesia; maternal age; pregnancy; second stage labor