Main author: Jóhanna Gunnarsdóttir
Institution or Company: Centre of Public Health Sciences, Faculty of Medicine, University of Iceland
Co-Authors, Institution or Company:
Emma M. Swift, Faculty of Nursing – Department of Midwifery, University of Iceland. Jóhanna Jakobsdóttir, Centre of Public Health Sciences, Faculty of Medicine, University of Iceland. Alexander Smárason, Institution of Health Science Research, University of Akureyri and Akureyri Hospital. Þórður Þórkelsson, Division of Neonatal Intensive Care, Children’s Medical Center, Landspitali. Kristjana Einarsdóttir, Centre of Public Health Sciences, Faculty of Medicine, University of Iceland.
Background: The rate of labor induction has risen steeply throughout the world. The aim of this project was to estimate changes in rates of adverse maternal and neonatal outcomes in Iceland between 1997 and 2018 and to assess whether the changes can be explained by an increased rate of labor induction.
Methods: Singleton, live births occurring between 1997 and 2018 that did not start by pre-labor cesarean were identified from the Icelandic Medical Birth Register (n=85,971). The study period was categorized into four periods. Rates of intrapartum cesarean births (CB), obstetric emergencies and neonatal outcomes were calculated, and adjusted risk ratios (aRRs) and 95% confidence intervals (CIs) were estimated with log binomial regression (reference: 1997-2001). Adjustments were made for maternal characteristics and, in a second step, for labor induction and gestational age.
Results: The rate of induction of labor increased from 13.6% in the period between 1997 and 2001 to 28.1% in the period between 2014 and 2018. The rate of intrapartum CB decreased between the 1997-2001 and 2014-2018 periods both for primiparous (aRR 0.76, 95% CI: 0.69 to 0.84) and multiparous women (aRR 0.55, 95% CI: 0.49 to 0.63). The rate of obstetric emergencies and adverse neonatal outcomes also decreased between these time periods. However, further adjustment for labor induction did not attenuate these associations.
Conclusions: The rate of both adverse maternal and neonatal outcomes was decreased through the study period. However, there was no evidence that this decrease could be explained by the increased rate of labor induction.