Academic journal article Australian Health Review

A Critical Review of Vaginal Birth Rates after a Primary Caesarean in Queensland Hospitals

Academic journal article Australian Health Review

A Critical Review of Vaginal Birth Rates after a Primary Caesarean in Queensland Hospitals

Article excerpt


Vaginal birth following primary Caesarean section (CS) is safe and appropriate for most women in a subsequent pregnancy.1,2 However, the number of women experiencing vaginal birth after CS (VBAC) is reported in the international literature as declining and coincides with an overall increase in CS rates.2,3 The purpose of the present paper is to identify the current incidence of vaginal birth after primary CS in Queensland hospitals, and compare this to rates reported in the literature.

Contributing factors to the VBAC dilemma

CS rates in Australia exceed the World Health Organization recommendation of 10-15% of births.4,5 The Netherlands is the only Organisation for Economic Co-operation and Development (OECD) country to report CS rates below 15%.6 The incidence of CS in Australia increased from 18% in 19917 to 25.4% in 2001 and 31.6% in 2010,8 yet there is no evidence to justify the current high CS rates.9

Although primary CS is a major contributor to overall CS rates, the leading reason for CS in Australia and other developed countries is attributed to repeat CS, which occurs in many women without an obvious indication for this intervention.3,10,11 According to Australian perinatal data for 2010, the highest rates of repeat CS are in the states of Queensland (84.4%) and Western Australia (86.7%) compared with the national average (83.6%).8

Women choosing to labour in their next birth following a primary CS achieve vaginal birth rates (74%) and other clinical outcomes similar to primiparous women.2,3 This means that although primary CS is an underlying problem, the next birth is a crucial event because subsequent CS incrementally increase the risk of adverse outcomes including uterine rupture, haemorrhage, hysterectomy and life-threatening conditions of placenta praevia, placenta accreta and placenta percreta.12-15 VBAC after primary CS increases the likelihood of subsequent vaginal birth success, and reduces the risk of uterine rupture with each further vaginal birth achieved.2 Therefore, apart from avoiding initial CS, the next birth after primary Caesarean is the ideal time to implement strategies to facilitate success in achieving vaginal birth inwomen without indication for repeat CS, and reduce dose-related morbidity of repeat CS.

Common clinical considerations for women undertaking VBAC relate to complications of uterine rupture for the mother and, as a consequence, possible permanent harm to the baby.16,17 Although uterine rupture is a risk in subsequent pregnancies following a lower-segment uterine incision, it is a rare event. In an Australian study (n = 29 008), the risk of complete uterine rupture was low for women having a repeat elective CS (0.01%) and for those women experiencing spontaneous labour (0.15%).18 This risk increased 3-5-fold for women whose labour was induced and 14-fold where spontaneous labour was augmented (1.91%). However, researchers in another Australian study indicated that to avoid the harm of uterine rupture in labour for one woman following primary CS, 25 000 additional CS were required.19 These population-based Australian studies were not included in a recent systematic review sponsored by the National Institutes of Health (NIH), which found the overall incidence for uterine rupture is 0.3%.2 Only one study20 within the NIH review concerned women birthing at term with one prior lower-uterine CS incision (n = 1408), finding a combined risk of 0.4% of uterine rupture for spontaneous, induced and augmented labours compared with 0% for elective repeat CS (P < 0.05).2

The NIH found that perinatal mortality for term infants in a pregnancy subsequent to a CS was lower in elective repeat CS compared with women who laboured (0.05% v. 0.13%).2 However, this finding included women with underlying medical complications at greater risk of adverse outcome regardless of labour or elective CS. Evidence assessed by the NIH indicated that 0.41 more perinatal deaths occurred among women attempting labour. …

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