To develop recommendations for the preferred delivery method for a pregnant woman who has had a prior low transverse Caesarean section and who has no contraindications for labour.

MEDLINE and references from the retrieved articles were searched for articles containing primary data and reflecting patients or current practice in the United States. The search terms included 'TOL', 'trial of scar', 'VBAC' and 'uterine rupture'. Studies from developing countries or before 1980 were excluded.

Study designs of evaluations included in the review

Observational studies or case series. No randomised trials were found.

Specific interventions included in the review

Trial of labour (TOL) or vaginal birth after Caesarean section (VBAC) and elective repeat Caesarean section (ERCS).

Participants included in the review

Pregnant women who have had a prior low transverse Caesarean section and who have no contraindications for labour, were included.

Outcomes assessed in the review

Maternal and infant outcomes were assessed. The maternal outcomes were:

mortality;

hysterectomy;

uterine rupture, defined as requiring surgical repair;

postpartum haemorrhage, defined as requiring transfusion;

bladder injury, defined as any bladder injury mentioned by the study's authors;

infection or fever, defined as the presence of any postpartum infection or fever; and

the length of hospital stay.

The infant outcomes were mortality, Apgar scores at 5 minutes, and the length of hospital stay.

How were decisions on the relevance of primary studies made?

The authors do not state how the papers were selected for the review, or how many of the authors performed the selection.

The authors do not state how the papers were assessed for validity, or how many of the authors performed the validity assessment.

The data were extracted by at least two reviewers using a structured form.

How were the studies combined?

The outcome data were combined using the confidence profile method. A fixed-effect Bayesian meta-analysis was undertaken when the studies produced similar outcome rates, or when rare outcomes occurred. In other cases, a random-effects approach was used.

How were differences between studies investigated?

The authors do not state how differences between the studies were investigated.

Two hundred and ninety-two articles were included.

The results were presented as the difference between TOL and ERCS in terms of the rate per 10,000 patients, where a negative result indicated a lower rate in the TOL group than in the ERCS group.

Maternal outcomes: death, -1.69 (95% confidence interval, CI: -5.13, 1.75); rupture, 23.9 (95% CI: 10.2, 37.7); hysterectomy, -3.26 (95% CI: -14.3, 7.75); bleeding, -58.6 (95% CI: -114.0, -32.5); infection or fever, -5.22 (95% CI: -923.0, -11.9); bladder injury, 15.4 (95% CI: -48.6, 79.0).

Infant outcome: overall death, 9.87 (95% CI: -9.82, 29.6); 5-minute Apgar score of less than 7, 85.0 (95% CI: 38.8, 131.0).

Patient preferences: about two thirds of the women preferred TOL over ERCS when they were interviewed during the last trimester of their pregnancy.

Charges were compared for length of stay. The mean length of hospital stay was 2.94 days for women who underwent TOL and 4.11 days for those who underwent ERCS. Infants had a mean length of stay of 2.99 days if their mothers underwent TOL, and 4.96 days if their mothers underwent ERCS.

A woman should be given information on both delivery methods and encouraged to undergo TOL, but her preference for ERCS should be respected.

The literature search and the inclusion criteria were clearly described, and the appropriate method was used to combine the evidence identified. The data from the individual studies were not presented, presumably due to the large number of articles included. The authors' conclusion seems reasonable given the fact that the available evidence was not from randomised trials. It is very likely that the women who underwent TOL were different from those who underwent ERCS, and therefore, the results of this review should be interpreted with great caution.

Randomised trials are required to evaluate the relative benefits and risk of TOL versus repeated Caesarean section.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.