Background: The induction of labor (IOL) is a common obstetric
intervention, steadily increasing (one out four pregnancies) in the last years.
This procedure should be considered only when there is a medical indication, and
when the benefits outweigh the maternal and/or fetal risks of waiting for
spontaneous onset of labor. Therefore, this study aims to compare the efficacy of
the IOL in terms of induction to delivery time, mode of delivery, and neonatal
well-being among different evidence-based and non-evidence-based indications.
Methods: This prospective study was conducted at the University Hospital
of Modena, between January and December 2020. We included singleton pregnant
women undergoing IOL, at the term. Intrauterine deaths, small for gestational age
fetuses 5th centile as well women with hypertensive disorders were excluded.
Women have been subdivided into 3 groups based on the indication to IOL:
premature rupture of membranes (PROM), post-date pregnancy (41 weeks + 3
days), and non-evidence-based indications (NEBI). The primary outcome is
the time occurring between IOL and delivery (TIME), analyzing separately by
parity. Moreover, mode of delivery and neonatal well-being were evaluated.
Results: A total of 585 women underwent IOL in the study period.
Overall, the median TIME between IOL and delivery was 19 hours, and the mean
cesarean section CS rate was 15.5% (91/585). Pregnancies induced for postdate
and non-evidence-based indications registered respectively a significantly higher
mean time (p 0.001), compared with women induced for PROM. This
occurred both in nulliparous and multiparous women. Moreover, at multivariate
analysis, the IOL TIME 24 hours was significantly influenced by Bishop
score (p = 0.000) and NEBI (p = 0.02) in nulliparous and by
gestational age (p = 0.000) and NEBI (p = 0.02) in multiparous.
Moreover, CS rate was significantly influenced by Bishop score (p = 0.003) in nulliparous and by gestational age (p = 0.01) in multiparous.
Finally, neonatal intensive care unit (NICU) admission resulted significantly
influenced only by gestational age (p = 0.002) in multiparous.
Conclusions: Our study confirms that IOL in non-evidence-based
indications, leads to an increase in induction to delivery time comparing with
women induced for PROM, both in nulliparous and multiparous women, thus it should
be justified and carefully evaluated. Further randomized controlled trials (RCT)
conducted in European/Italian settings are needed to determine the perinatal
outcomes of IOL in non-evidence-based indications.