Does starting labor artificially (induction) affect the likelihood of scar rupture?

The research findings here are mixed. The most recent major evidence report on this topic concluded that there is probably an increased risk of uterine rupture when labor is induced after 40 weeks, but not when labor is induced prior to 40 weeks.Guise, J.M., Eden, K., Emeis, C., . . . McDonagh, M. (2010). Vaginal birth after cesarean: New insights. Evidence Report/Technology Assessment No.191. (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality.

The risk may depend on the methods used to induce labor. Medical agents used to soften and shorten the cervix (the opening to the uterus) may increase the likelihood that the scar will open and lead to problems in labor. Some researchers think these agents may soften (and thus weaken) the uterine scar as well. These agents belong to a family of hormone-like substances called prostaglandins and include Cytotec, Cervidil and Prepidil. Cytotec (also known as misoprostol) appears to be the riskiest option and experts agree it should not be used in VBAC labors. Use of a Foley catheter, a mechanical method to soften and open the cervix, does not appear to be any riskier than medical agents, but more research is needed.Guise, J.M., Eden, K., Emeis, C., . . . McDonagh, M. (2010). Vaginal birth after cesarean: New insights. Evidence Report/Technology Assessment No.191. (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality.

Using synthetic oxytocin (Pitocin or "Pit") by itself to try to start (induce) labor may also increase the likelihood that the scar will give way, but oxytocin appears to be safer than prostaglandins. Giving oxytocin in labor to strengthen contractions (labor augmentation or stimulation) may also increase the risk of scar problems.Guise, J.M., Eden, K., Emeis, C., . . . McDonagh, M. (2010). Vaginal birth after cesarean: New insights. Evidence Report/Technology Assessment No.191. (Prepared by the Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-2007-10057-I). AHRQ Publication No. 10-E003. Rockville, MD: Agency for Healthcare Research and Quality.

Visit the Induction section to learn more about this topic.