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27: Evaluation of failed induction of labor

      Objective

      Data are limited for determining the definition of failed induction. We evaluated maternal and neonatal morbidity according to duration of oxytocin administration in latent labor after rupture of membranes (ROM).

      Study Design

      In the Consortium of Safe Labor study (2002-2008), we included 9,772 nulliparas and 8,698 multiparas with singleton deliveries ≥37 weeks undergoing induction with cervix ≤ 2 cm dilation. Latent labor was defined as last cervical examination <6 cm in nulliparas and <5 cm in multiparas. Vaginal delivery (VD) rates, maternal morbidity (chorioamnionitis, endometritis, and postpartum hemorrhage [PPH]) and neonatal morbidity (neonatal intensive care unit [NICU] admission, NICU stay longer than 72 hours (hrs), continuous positive airway pressure, and neonatal sepsis) were evaluated for women who were in latent labor after 6, 9, 12, and 18+ hrs of oxytocin and ROM.

      Results

      After 6 hrs, 54% of nulliparas and 85% of multiparas entered active labor. Duration of latent labor was associated with lower VD rates (Figure 1). Only 6.5% of nulliparas and 1.1% of multiparas remained in latent labor after 12 hrs; among them, 36.7% of nulliparous and 57.4% of multiparous delivered vaginally. Only 1.4% of nulliparas and 0.3% of multiparas remained in latent labor after 18+ hrs. Maternal morbidity increased regardless of parity with longer latent phase (Figure 2). Chorioamnionitis was significantly higher in both nulliparas and multiparas after 6, 9, 12, and 18+ hrs. Endometritis was significantly higher in nulliparas after 6, 9, and 12 hrs. PPH was significantly higher in nulliparas after 6 and 9 hrs, and in multiparas after 12 hrs. Neonatal morbidity was not associated with duration of oxytocin and ROM in latent labor.

      Conclusion

      After 18 hours of oxytocin and ROM, 98.6% of nulliparas and 99.7% of multiparas delivered. Although maternal morbidity was associated with duration, neonatal morbidity was not increased. Our data support oxytocin administration after ROM for at least 12-18 hrs before considering an induction as failed as long as maternal and fetal condition allows.
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