Reader Comments

Post a new comment on this article

Does this study provide convincing evidence?

Posted by serenadonati on 20 Mar 2012 at 09:15 GMT

Serena Donati, Sabrina Senatore and Laura Lauria
National Centre for Epidemiology, Surveillance, and Health Promotion, Istituto Superiore di Sanita`-Italian National Institute of Health, Rome, Italy

We thank the authors for publishing the paper Planned Vaginal Birth or Elective Repeat Caesarean: Patient Preference Restricted Cohort with Nested Randomised Trial (1) which encourages the discussion of this interesting subject. Italy ranks first in Europe with 38% of deliveries by caesarean section and the national proportion of vaginal birth after caesarean (VBAC) is 10%. In accordance with the international guidelines (2-5) the recently published Italian national guidelines (6) recommend VBAC for women with prior caesarean. The acceptance rate of 0.9% to randomization among eligible women (22/2345) in the Crowther study (1) clarifies the inappropriateness of the randomized clinical trial design. Therefore, despite the prospective “restriced” cohort design, the study is an observational study. Furthermore, it is not population based and authors do not describe the characteristics of the 14 participating hospitals. According to the study selection criteria, 2345 women were enrolled as eligible for trial of labour (TOL). Of these, 47% (1108 women) preferred to choose a repeat caesarean. This figure leads one to suspect that nonmedical factors that influence the utilization of TOL play an important role in decision making and patient access, but information are lacking. The primary outcome of the study is a composite of death or serious outcomes including conditions of different severity that could mislead the study conclusion. The authors performed an intention to treat analysies without describing the clinical indications for the elective cesarean sections performed among 334 women (27%) of those enrolled as eligible for VBAC. Finally, more than half (57%) of the women whose outcomes were recorded in the VBAC group underwent instead a cesarean section. Since the outcomes are not described for the subgroups, results are hard to interpret. Moreover, adjustment for possible confounders is incomplete (e.g adjustment for maternal age is missing) and criteria adopted for previous TC indication adjustment are lacking. Also generalization of study results to the entire population of women with prior cesarean is, in our opinion, not correct. In fact, despite the authors declaration that they refer only to women with a single prior cesarean, the emerging evidence of serious harm relating to multiple caesareans is ignored. We, therefore, believe that this study does not provide convincing evidence of the greater safety of elective repeat caesarean section compared to VBAC that, in our opinion, is still a reasonable and safe choice for the majority of women with prior caesarean.

1. Crowther A.C., Dodd J.M., Hiller J.E. et al. (2012) Planned vaginal birth or elective repeat caesarean:patient preference restricyted cohort with nested randomised trial. Plos Medicine 9(3): e10001192. doi:10.1371/journal.pmed.1001192
2. Guise J-M, Eden K, Emeis C, Denman MA, Marshall N, Fu R, Janik R, Nygren P, Walker M, McDonagh M. Vaginal Birth After Cesarean: New Insights. Evidence Report/Technology Assessment No.191. (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality. March 2010.
3. Royal College of Obstetricians and Gynaecologists (RCOG) (2007) Birth after caesarean birth: Green top guideline no 45. London: RCOG Press
4. National Collaborating centre for women’s and children’s health (NICE) Caesarean Section. RCOG Press, London (2011).
5. The American College of Obstetricians and Gynecologists - ACOG Practice Bulletin n.115 Vaginal Delivery after previous cesarean delivery Obstetrics and Gynecology Vol.116, 450-63, August 2010
6. Sistema Nazionale per le Linee Guida (SNLG) Taglio Cesareo: una scelta appropriate e consapevole. Seconda parte. Linea Guida 22, Istituto Superiore di Sanità (2012).

No competing interests declared.