Office of Epidemiology and Research, Division of Research

Advancing Applied MCH Research

(SDAS) Elective Induction of Labor: Outcomes by Gestational Age.

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Project Number: R40 MC 25694
Grantee: Oregon Health & Science University
Department/Center: OBGYN/Perinatology
Project Date: 02/01/2013

Final Report


Principal Investigator

Aaron Caughey, MD
Professor and Chair
3181 SW Sam Jackson Park Road
Portland, OR  97239-3098
Phone: 503-494-2999


  • Women/Maternal
  • Prenatal
  • Perinatal/Infancy (0-12 months)


This study examines elective induction of labor, a common intervention for which evidence about outcomes is sparse. The primary outcome of interest is its impact on cesarean delivery, though many other maternal and neonatal outcomes will be examined including perinatal mortality. Labor induction and cesarean are essential public health concerns, due to their frequency and their impact on population health (both in immediate clinical settings and over the life-course). Our proposed study is distinguished from most prior studies in the use of expectant management as the comparison group. Most observational studies compare induction of labor to spontaneous labor at the same gestational age. However, the proper clinical comparison would be between induction of labor at the current gestation age to expectant management which would be delivery beyond the current gestational age. We will also stratify more finely on gestational age than prior studies, examining outcomes separately for elective induction at 37, 38, 39 and 40 weeks' gestation, which is important because the risks and benefits of elective induction appear to vary by gestational age. The current study also distinguishes itself by its large, diverse population. Based on preliminary analyses, we believe we will have sufficient power for many comparisons across a range of subgroups including by race/ethnicity and maternal obesity. Our findings will affect clinical practice because current data on risks and benefits of elective induction are limited. Our findings could immediately shape clinical practice by influencing the decisions of pregnant women and their providers. These findings also stand to benefit systems level factors, health policy, health disparities, and population health. Because obstetrical interventions are of great and increasing interest to hospital administrators and public health researchers and practitioners, this study stands to improve our understanding of population health and improve interventions. Epidemiologic and public health research increasingly concerns itself with the impact of cesarean delivery on childhood and later life health outcomes, so elucidating the etiology of cesarean delivery can help address the cesarean epidemic. Specifically, we believe the project addresses components of MCH Strategic Research Issues (SRI) 2, 3, and 4. We will be specifically examining the potential differences in obstetric management, specifically induction of labor by race/ethnicity, but also the potential impact of these management differences on maternal and neonatal outcomes consistent with SRI #2. Elective induction of labor, cesarean delivery, and perineal lacerations are commonly used as measures of quality. However, it is unclear whether these are appropriate metrics. This work will endeavor to gain more depth of understanding of how these interventions and outcomes are related and whether they are associated with other measures of morbidity and mortality which is related to SRI #3. Finally, SRI #4 is concerned with long-term development of MCH populations. While we will not examine long-term outcomes, a number of fetal and neonatal outcomes are related to long-term developmental outcomes such as birthweight and gestational age. Further, it has been shown that cesarean delivery is associated with childhood obesity, thus an earlier intervention that increases or reduces cesarean delivery may have long-term downstream impacts.


Listed is descending order by year published.

Snowden JM, Darney B, Cheng YW, et al. Systems Factors in Obstetric Care: The Role of Daily Obstetric Volume. Obstet Gynecol. 2013; 122:851-7.

Darney BG, Snowden JM, Cheng YW, et al. Elective Induction of Labor at Term Compared to Expectant Management: Maternal and Neonatal Outcomes. Obstet Gynecol. 2013; 122:761-9.


Cesarean, Health Care Utilization, Health Disparities, Labor & Delivery, Obesity & Weight, Postpartum, Pregnancy, Perinatal

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