- Between July 1, 2016, and June 30, 2019, 4,123 nulliparous women had labor induced and delivered a liveborn singleton at 39 to 41-6/7 weeks of gestation at Massachusetts General Hospital and its partner hospitals
- 82 women (2%) experienced failure of induction according to the Obstetric Care Consensus criteria of the American College of Obstetricians and Gynecologists and the Society for Maternal–Fetal Medicine
- In a comparison of those 82 women and 328 controls, risk factors associated with failed induction of labor were obesity, shorter stature and cervical dilatation <2 cm at admission
- The rate of failed induction of labor was low even among women who had labor induced for maternal or fetal indications
In 2014, the American College of Obstetricians and Gynecologists and the Society for Maternal–Fetal Medicine published a joint Obstetric Care Consensus on diagnosing failed induction of labor. However, there is still little information about the incidence of failed induction using this standardized definition.
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In a case–control study, Mark A. Clapp, MD, MPH, a specialist in the Maternal-Fetal Medicine Program, and colleagues in the Department of Obstetrics and Gynecology at Massachusetts General Hospital found that failed induction of labor according to the standardized definition occurs infrequently, even among women who have certain risk factors they identified. Their report appears in Obstetrics & Gynecology.
Between July 1, 2016, and June 30, 2019, at Mass General and its partner hospitals, 4,123 nulliparous women had labor induced and delivered a liveborn singleton at 39 to 41-6/7 weeks of gestation. Failed induction was defined according to Obstetric Care Consensus criteria:
- Cesarean delivery was required for "failure to progress" or "failed induction" in the first stage of labor
- The last documented cervical dilatation was <6 cm
- Oxytocin was administered for ≥12 hours after rupture of membranes
82 women (2%) experienced a failed induction. Each was matched by hospital site and date of admission with four nulliparous control subjects, induced during the same time period, who did not meet the criteria for failed induction.
Risk Factors and Protective Factors
- Factors positively associated with failed induction were body mass index (BMI) at delivery of 30.0–39.9 kg/m2 (adjusted OR, 2.42) and BMI ≥40 kg/m2 (aOR, 7.93) compared with BMI <30 kg/m2
- Factors negatively associated with failed induction were height (aOR, 0.89 per additional inch) and cervical dilatation at the admission of ≥2 cm (aOR, 0.30)
- Indications for induction—fetal concern, late-term or maternal comorbidities (e.g., advanced maternal age, chronic hypertension, hypertensive disorders of pregnancy, pregestational or gestational diabetes)—did not influence the odds of failed induction
The information from this study can be used to reassure women that the overwhelming majority of women who are induced achieve active labor, even those induced for maternal medical or fetal indications.
One question is whether the definition of failure of induction is appropriate for women with obesity. 12 hours of oxytocin administration may be too conservative a criterion—some women with high BMI might go on to deliver vaginally if given more time in the latent phase.
Learn more about the Maternal-Fetal Medicine Program
Refer a patient to the Obstetrics Program at Mass General