title: Factors affecting vaginal birth after caesarean section at Middlemore Hospital, Auckland, New Zealand.
abstract: OBJECTIVE
  To determine factors associated with vaginal birth after caesarean section (VBAC) in women delivering at Middlemore Hospital (MMH).
  
  
  METHODS
  Retrospective descriptive study. All women in 2008-2009 who had a previous caesarean section and was deemed suitable for a trial of labour (TOL).
  
  
  RESULTS
  Of the 1543 women who had one or more previous caesarean sections, 806 (52.2%) were deemed suitable for a TOL by an obstetrician and self-selected to have a VBAC. Of the 806 women who had a TOL, 592 (73%) had a VBAC. Of women who had a previous VBAC, 257 (91%) delivered vaginally again compared to 332 (64%) without such a history (OR 3.69; 95%CI 1.83-7.43). Increasing parity increased the chances of another vaginal delivery. Variables that led to a failed VBAC were: a BMI =25 in women of single parity (OR 0.47, 95%CI 0.24-0.91), labour augmentation (OR 0.63, 95%CI 0.43-0.93) and epidural analgesia (OR 0.18, 95%CI 0.12-0.28).
  
  
  CONCLUSIONS
  The VBAC rate at MMH in 2008-2009 was 73% and was higher in women who had a previous VBAC. The VBAC rate is lower in women with a high BMI of single parity and where progress of labour was slow. This information is important in counselling women with a previous caesarean section who are considering a VBAC.
authors.affiliation: Pacific Women's Health Research and Development Unit, Department of Obstetrics and Gynaecology, University of Auckland, Middlemore Hospital, PB 93311, Auckland, New Zealand. aekeroma@middlemore.co.nz.
authors.forename: Anna-Marie
authors.initials: AM
authors.lastname: van der Merwe
authors.forename: John M D
authors.initials: JM
authors.lastname: Thompson
authors.forename: Alec J
authors.initials: AJ
authors.lastname: Ekeroma
mesh_terms: D000293:Adolescent; D000328:Adult; D016362:Analgesia, Obstetrical; D015992:Body Mass Index; D017604:Cesarean Section, Repeat / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D009520:New Zealand; D010298:Parity; D011247:Pregnancy; D012189:Retrospective Studies; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*; D055815:Young Adult