The authors, all from Penn, investigated four different methods of inducing labor to evaluate which would reduce the amount of time it takes until delivery. Women present to the hospital at various points in their labor course, making it very challenging to compare labor induction methods in an observational study. The authors overcame this by randomizing women to the different induction methods, so that there was balance across the study arms. Each of the induction methods was then used in a standardized approach to minimize practice differences among physicians.
To estimate how various induction methods affected time to delivery, the authors used survival-analysis methods. They assumed cesarean section as a "censoring event"—so the duration of labor up to the point of the cesarean was included in the analysis. Previous work has often ignored this important aspect and so has underestimated the true duration of labor.
The Penn team showed that using a balloon catheter in combination with a prostaglandin drug called misoprostol reduces a woman’s time in labor by about four hours. The results of the study could save nearly 2.4 million hours of labor each year for women who need to have their labor induced. In recognition its important implications, the article won a 2016 Roy M. Pitkin Award from the editors of Obstetrics & Gynecology.