The effects of induction of labor prior to post-term in low risk pregnanices: a systematic review.

Background: The last decades reveal a two- to four-fold increase in the rate of induction of labor in the Scandinavian and other developed countries. Thus, 25% of all deliveries in Denmark were induced in 2014. Routine induction one week past estimated date of delivery can explain a substantial part of this increase. Aim: To assess the evidence behind the policy of routine labor induction at 41 completed gestational weeks (41+0 to 41+6 weeks) instead of awaiting spontaneous labor until 42 completed weeks where induction is performed (42+0 to 42+6 weeks). Method: A systematic literature search was performed in PubMed, CINAHL, Cochrane and other relevant databases and all studies conducted 1994-2014 and published in English, Danish, Swedish, or Norwegian language were included. Randomized and cohort studies were included but analyzed separately. Out of 730 identified papers, 7 fulfilled criteria for further analysis. Results: Routine induction (41+0/6) versus awaiting another week before induction (42+0/6) was associated with an increased risk of precipitate labor, chorioamnionitis, uterine rupture, and pH < 7.10, and a decreased risk of oligohydramnios. There was no difference in cesarean sections, postpartum hemorrhage, shoulder dystocia, meconium aspiration, 5-minute Apgar < 7 or admission to NICU. Analysis of intrauterine and perinatal deaths was not possible due to lack of adequate information in the included papers. Furthermore the review had very sparse information on normal adverse effects of induction of labor and about the resource requirements due to the vast amount of women induced. Conclusion: We found that the widespread use of routine induction is not supported by solid evidence.