For several years now there has been a
campaign to reduce non-medically indicated labor inductions prior to 39 weeks
of gestation (see our February 8, 2011 Patient Safety Tip of the Week “Inducing
Too Early”). That campaign, originally sponsored by the March of Dimes,
Leapfrog Group, California Maternal Quality Care Collaborative and the
California Department of Public Health; Maternal, Child and Adolescent Health
Divisions, and later adopted by the American College of Obstetricians and
Gynecologists (ACOG) highlighted the risks to newborns delivered prior to 39
weeks of gestation and provided tools to help avoid “elective” inductions prior
to 39 weeks. We’ve been on board for that campaign.
We and others have also speculated that those
early inductions might also be leading to more cesarean sections (see our
September 7, 2010 Patient Safety Tip of the Week “Patient
Safety in Ob/Gyn Settings” and our September 2013 What’s New in the Patient
Safety World column “Full-Time
Laborists Reduce C-Section Rates”).
Now a new study challenges both concepts.
Researchers at the Oregon Health & Science University (Darney
2013) reviewed data on all the
deliveries in the state of California in 2006 and applied better methods to identify
cases in which inductions lacked medical indications and then compared maternal
and neonatal outcomes between those with non-medical inductions vs. expectant
management. They found that the odds of cesarean section was actually
significantly lower in women having inductions without medical indication at
weeks 37, 38, 39, and 40 among both multiparous and nulliparous women.
Moreover, there was no difference in the risk
for severe lacerations, operative vaginal delivery, perinatal death, NICU
admission, respiratory distress, or macrosomia between the groups at any week
studied. There was an increased risk of hyperbilirubinemia in infants with
inductions lacking medical indication at 37 and 38 weeks of gestation and an
increased risk of shoulder dystocia at week 39.
Note that another study published about a year ago (Stock 2012) had found that elective induction of labor between weeks 37 and 40 was associated with decreased odds of perinatal mortality compared to expectant management and did not increase the risk of cesarean sections. Admissions to a neonatal unit were, however, increased in those cases having elective induction prior to 41 weeks.
The Darney study highlights the difficulties in interpreting conclusions that come from retrospective analysis of data (on which most prior recommendations have been based). The authors note that efforts to reduce induction of labor without medical indication before 39 weeks of gestation (or to reduce induction without an indication overall) are based on a relatively limited literature. They caution that focus on induction of labor as a quality metric in obstetrics must be evidence-based. Use of a standard method to classify induction without medical indication would be critical for prospective studies to further answer these important questions.
Darney BG, Snowden JM, Cheng YW, et al. Elective Induction of Labor at Term Compared With Expectant Management: Maternal and Neonatal Outcomes. Obstetrics & Gynecology 2013; published ahed of print 6 September 2013
Stock SJ, Ferguson E, Duffy A, et al. Outcomes of elective induction of labour compared with expectant management: population based study. BMJ 2012; 344: e2838 Published 10 May 2012