Abstract
There are currently no up-to-date evidence-based recommendations on the preferred
method to induce labour after previous Caesarean section, especially for patients
with unripe cervix, as
randomised controlled studies are lacking. Intravenous oxytocin and misoprostol are
contraindicated in these women because of the high risk of uterine rupture. In women
with ripe cervix
(Bishop Score > 6), intravenous administration of oxytocin is an effective procedure
with comparable rates of uterine rupture to those with spontaneous onset of labour.
Vaginal
prostaglandin E2 (PGE2 ) and mechanical methods (balloon catheters, hygroscopic cervical dilators) are effective
methods to induce labour in pregnant women with unripe
cervix and previous Caesarean section. According to current guidelines, the administration
of PGE2 is associated with a higher rate of uterine rupture compared to balloon
catheters. Balloon catheters are therefore a suitable alternative to PGE2 to induce labour after previous Caesarean section, even though this is an off-label
use. In addition to
two meta-analyses published in 2016, 12 mostly retrospective cohort/observational
studies with low to moderate levels of evidence have been published on mechanical
methods of cervical
ripening after previous Caesarean section. But because of the significant heterogeneity
of the studies, substantial differences in study design, and insufficient numbers
of pregnant women
included in the studies, it is not possible to make any evidence-based recommendations
based on these studies. According to a recent meta-analysis, the average rate using
balloon catheters
is approximately 53% and the average rate after spontaneous onset of labour is 72%.
The uterine rupture rate was 0.2–0.9% for vaginal PGE2 and 0.56–0.94% for balloon catheters and
is therefore comparable to the uterine rupture rate associated with spontaneous onset
of labour. According to the product informations, hygroscopic cervical dilators (Dilapan-S)
are
currently the only method which is not contraindicated for cervical ripening/induction
of labour in women with previous Caesarean section, although data are insufficient.
Well-designed,
randomised, controlled studies with sufficient case numbers comparing balloon catheters
and hygroscopic cervical dilators with mechanical methods and vaginal prostaglandin
E2 /oral
misoprostol are therefore necessary to allow proper decision-making.
Keywords induction of labour after Caesarean section - balloon catheter - hygroscopic cervical
dilators - prostaglandins - uterine rupture
