Balloon ripening in TOLAC: lower rupture odds than prostaglandins

Design

Systematic review and meta-analysis; 18 non-randomised studies and 2 randomised trials

Population

Trial of labour after one low-transverse caesarean; 28,035 observations, 5,516 balloon exposures

Primary outcome

Complete uterine rupture

Effect

vs prostaglandins OR 0.43 (95% CI 0.26 to 0.72); vs spontaneous labour OR 1.29 (0.90 to 1.84); dehiscence OR 1.86 (1.06 to 3.29)

A systematic review in AJOG (published 29 September) pooled 18 non-randomised studies and two randomised trials of women attempting vaginal birth after a previous low-transverse caesarean, in whom a Foley, single- or double-balloon catheter was used to ripen the cervix. There were 28,035 study observations, 5,516 of them balloon exposures. Because amniotomy, oxytocin or both followed the catheter in almost every protocol, the authors treat the exposure as a balloon-based induction strategy, not the device alone.

Against prostaglandin induction, complete uterine rupture was less likely with the balloon strategy (OR 0.43, 95% CI 0.26 to 0.72), an absolute difference of about 19 fewer ruptures per 1,000. No difference was detected against spontaneous labour (OR 1.29, 0.90 to 1.84) or oxytocin alone, though the oxytocin comparison was very imprecise. Scar dehiscence, by contrast, was reported more often after balloon-based induction (OR 1.86, 1.06 to 3.29).

This supports what many units already do: when induction is needed after one caesarean and the cervix is unfavourable, mechanical ripening is a reasonable first choice over prostaglandins. GRADE certainty was very low throughout, so this is a basis for counselling, not a guarantee of safety. Continuous fetal monitoring and immediate theatre access remain the conditions of offering it.

• When induction is indicated after one low-transverse caesarean, discuss a balloon catheter as the ripening option before prostaglandins.
• Counsel that rupture risk with balloon induction looked similar to spontaneous labour, but the evidence is very low certainty.
• Mention that scar dehiscence was reported more often after balloon-based induction.
• Keep continuous fetal monitoring and immediate access to emergency caesarean as conditions of any induced TOLAC.
• Document the counselling, including the alternative of planned repeat caesarean.

Why it matters

It gives units a number to counsel with when choosing a ripening method after a scar, where the fear of rupture often drives women straight to repeat caesarean.

Don't overread it

Almost all the data are observational and very low certainty; the catheter cannot be separated from the amniotomy and oxytocin that followed it.

The statistics, in plain English

An odds ratio of 0.43 means the odds of rupture were a little under half those with prostaglandins; in absolute terms about 19 fewer ruptures per 1,000 inductions. Against spontaneous labour the interval (0.90 to 1.84) crosses 1, so no difference was shown, but a modest increase cannot be ruled out. The higher dehiscence figure matters because dehiscence is usually less dangerous than rupture but is not nothing.

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