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Elective induction of labor at 39 weeks compared with expectant management: a meta-analysis of cohort studies

Published:February 25, 2019DOI:https://doi.org/10.1016/j.ajog.2019.02.046

      Background

      Elective induction of labor at 39 weeks among low-risk nulliparous women has reduced the chance of cesarean and other adverse maternal and perinatal outcomes in a randomized trial, although its clinical effectiveness in nonresearch settings remains uncertain.

      Objective

      To perform a systematic review of observational studies that compared elective induction of labor at 39 weeks among nulliparous women with expectant management and to use meta-analytic techniques to estimate the association of elective induction with cesarean delivery, as well as other maternal and perinatal outcomes.

      Study Design

      Studies were eligible for this meta-analysis only if they: (1) were observational; (2) compared women undergoing labor induction at 39 weeks with women undergoing expectant management beyond that gestational age; (3) included women in the induction group only if they had no other indication for labor induction at 39 weeks; and (4) provided data specifically for nulliparous women. The predefined primary outcome was cesarean delivery, and secondary outcomes representing other maternal and perinatal morbidities also were evaluated. Outcome data from different studies were combined to estimate pooled relative risks with 95% confidence intervals using random-effects models.

      Results

      Of 375 studies identified by the initial search, 6 cohort studies, which included 66,019 women undergoing elective labor induction at 39 weeks and 584,390 undergoing expectant management, met inclusion criteria. Elective induction of labor at 39 weeks was associated with a significantly lower frequency of cesarean delivery (26.4% vs 29.1%; relative risk, 0.83; 95% confidence interval, 0.74–0.93), as well as of peripartum infection (2.8% vs 5.2%; relative risk, 0.53; 95% confidence interval, 0.39–0.72). Neonates of women in the induction group were less likely to have respiratory morbidity (0.7% vs 1.5%; relative risk, 0.71; 95% confidence interval, 0.59–0.85); meconium aspiration syndrome (0.7% vs 3.0%; relative risk, 0.49; 95% confidence interval, 0.26–0.92); and neonatal intensive care unit admission (3.5% vs 5.5%; relative risk, 0.80; 95% confidence interval, 0.72–0.88). There also was a lower risk of perinatal mortality (0.04% vs 0.2%; relative risk, 0.27; 95% confidence interval, 0.09–0.76).

      Conclusion

      This meta-analysis of 6 cohort studies demonstrates that elective induction of labor at 39 weeks, compared with expectant management beyond that gestational age, was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, including respiratory morbidity, intensive care unit admission, and mortality.

      Key words

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      Linked Article

      • Should we offer elective induction of labor to nulliparous women at 39 weeks?
        American Journal of Obstetrics & GynecologyVol. 221Issue 3
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          We have read with great interest the metaanalysis of cohort studies by Grobman et al1 that compared elective induction of labor at 39 weeks gestation among nulliparous women with expectant treatment. The authors illustrated that elective induction of labor at 39 weeks gestation was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, which include respiratory morbidity, intensive care unit admission, and death. These results further confirm the conclusion of the A Randomized Trial of Induction Versus Expectant Management (ARRIVE) that was published in August 2018,2 which led a revolution in the management of pregnancies beyond 39 weeks gestation in low-risk women, with many clinicians dismissing expectant management in favor of induction.
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      • Reply
        American Journal of Obstetrics & GynecologyVol. 221Issue 3
        • Preview
          We thank the authors for their interest in our metaanalysis concerning labor induction at 39 weeks of gestation.1 We could not agree more with their statement that this intervention should not be a “reflex” based on gestational age alone. Indeed, labor induction at 39 weeks of gestation without other indication should be initiated not as a reflex action but in the context of patient choice and a shared decision-making framework. Part of such a framework is the conveyance of accurate information based on available data.
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