BACKGROUND AND PURPOSE:

• There is some concern that the increasing trend in induction of labor (IOL) may increase the overall rate of cesarean in the population
• Kruit et al. (BMJ Open, 2022) investigated the influence of increasing rates of IOL on the rate of caesarean delivery

METHODS:

• Population-based retrospective study
• Population
  • Pregnancies in Finland from 2008 to 2019
  • Data derived from The Finnish Medical Birth Register
• Exposures
  • IOL
• Study design
  • Medical Birth Register data are compiled at the time of birth | Based on mother’s prenatal charts, the Central Population Register (live births) and the Cause of Death Register (stillbirths and neonatal deaths)
  • Three study periods
    • 2008–2010: Period 1
    • 2011–2013: Period 2
    • 2014–2016: Period 3
    • 2017–2019: Period 4
• Primary outcomes
  • Rates of IOL and caesarean delivery

RESULTS:

• 663,024 live births during study period
• The rate of labor induction increased during the study (P<0.001)
  • Period 1: 17.8%
  • Period 4: 30.3%
• Total cesarean delivery rate: 16.5%
• Overall cesarean delivery rate increased (p<0.001)
  • Period 1: 16.3%
  • Period 4: 17.0%
• The rate of cesarean delivery following IOL slightly declined over the same period (P<0.001)
  • Period 1: 15.41%
  • Period 4: 15.35%
• In multivariate logistic regression analysis, IOL was associated with a reduced risk for caesarean delivery
  • OR 0.72 (95% CI, 0.71 to 0.74)
• During the study, the rates of the following increased in the population
  • Advanced maternal age (P<0.001)
    • Period 1: 18.0%
    • Period 4: 23.5%
  • Obesity (P<0.001)
    • Period 1: 11.4%
    • Period 4: 15.1%
  • Gestational diabetes
    • Period 1: 9.8%
    • Period 4: 23.3%

CONCLUSION:

• Over a 12-year period, IOL in Finland has increased by 70%, but cesarean delivery rates have remained relatively stable
• IOL increase likely due to higher maternal age at delivery and increasing obesity and GDM rates over the study period  
• The authors state

The almost doubled rate of labour induction in Finland has not led to a significant increase in the rate of caesarean delivery

…after adjustment for birth year and background demographics, IOL was associated with a reduced risk for emergency caesarean delivery

Learn More – Primary Sources:

Breaking the myth: the association between the increasing incidence of labour induction and the rate of caesarean delivery in Finland – a nationwide Medical Birth Register study

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