Labor induction using modified metreurynters plus oxytocin at an institution in Japan: a retrospective study

The authors evaluated the effectiveness and safety of "neo-metoro" or 'mini-metoro" metreurynters plus oxytocin for labor induction and assessed differences in parturition outcomes, according to the metreurynter used at induction initiation.

The authors retrospectively reviewed 146 consecutive women with live singleton pregnancies, and who underwent induction. Parturition outcomes were vaginal delivery achieved within the planned schedule (VDPS), vaginal delivery finally achieved (VDF), and induction-to-delivery interval (IDI). Women were divided into neo-metoro, mini-metoro, and without metreurynter groups based on metreurynter use at induction initiation. The authors examined the relationships of metreurynter groups with factors, parturition outcomes, and adverse events. In 113 women who underwent two-day induction, the authors calculated IDI and adjusted odds ratio (AOR) for achieving delivery per unit time.

VDPS rates were 65% in nulliparous and 81% in multiparous women. VDF rates were 78% in nulliparous and 96% in multiparous women. AORs for VDPS were 0.30 in nulliparous women and 0.18 in Bishop score (BS) 1-3 class. AORs for VDF were 0.04 in BS1-3 class and 0.14 in BS4-5 class. In 113 women undergoing two-day induction, AORs for achieving delivery per unit time were 0.45 in nulliparous women, 0.46 in obese women, and 0.48 in BS1-3 class. Neo-metoro use at induction initiation tended to reduce IDI.

Labor induction using these metreurynters plus oxytocin is safe and effective. The advantages of neo-metoro over mini-metoro use at induction initiation remain unclear; neo-metoro use at induction initiation may reduce IDI.