RCT design
A multi-center randomized controlled trial was undertaken across eight
Australian maternity hospitals, between September 2015 and October 2018.
The study compared the use of outpatient balloon catheter cervical
priming IOL with inpatient PG (Dinoprostone) vaginal gel or tape. The
methods are described in detail elsewhere (16). In summary, eligible
women had a live singleton pregnancy, cephalic presentation, at or
beyond 37+0 weeks gestation, and were undergoing IOL for low-risk
indications. Women presented to hospital in the early evening. Those
randomized to the inpatient-PG group were admitted to hospital,
administered PG as 2mg Dinoprostone vaginal gel (Prostin) or 10mg
Dinoprostone controlled-release vaginal tape (Cervidil), and then
remained as an inpatient until birth. Women randomized to the
outpatient-balloon group had a double-balloon catheter (Cervical
Ripening Balloon plus stylet; Cook Medical, Bloomington, US) placed
during a digital vaginal examination. Following 30 minutes of
observation, the woman was given written information about the reasons
to return earlier and how to call the hospital, and discharged home for
approximately 12 hours. For women in both groups, early clinical review
occurred if there was vaginal bleeding, fluid loss, painful
contractions, expulsion of the balloon, or the woman needed pain relief.
Otherwise, women were reviewed in birth suite the following morning,
approximately 12 hours after commencement of her IOL. At this review, an
amniotomy was attempted, and a Syntocinon infusion commenced as soon as
possible. Women completed a written questionnaire postpartum (prior to
hospital discharge), measuring their healthcare experience and this
included an assessment of health-related quality of life. The primary
outcome measure was a composite measure of neonatal outcomes. Healthcare
cost was a secondary outcome measure.