Expert Commentary

Uterine rupture and dehiscence and VBAC

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References

THE QUESTION:
Does the risk of uterine rupture and dehiscence increase with a previous cesarean delivery?

Past studies

Prior research has demonstrated that patients undergoing a trial of labor after a cesarean delivery have an increased risk (1 in 200) of uterine rupture and dehiscence (URD).

This study

This 10-year review and case-control study examined 25,718 deliveries at a regional medical center to describe complications and identify risk factors for URD. During this period, 11 uterine ruptures and 10 uterine dehiscences occurred, along with 1 maternal death and 3 neonatal deaths. Other complications included intrapartum nonreassuring fetal status (67%), 5-minute Apgar score of less than 7 (52%), maternal blood transfusion (24%), neonatal hypoxic injury (14%), hysterectomy (14%), and endometritis (10%).

URD was independently associated with a fetal weight of greater than 8.8 lb, nonreassuring fetal status, oxytocin administration, and previous cesarean delivery. On the other hand, internal fetal monitoring was associated with a reduced risk of URD. The researchers concluded that in order to reduce the risk of URD, a delivery plan must include a cesarean history and fetal macrosomia assessment, along with the judicious use of oxytocin and intrapartum monitoring for nonreassuring fetal status.

Find this study

Diaz SD, Jones JE, Seryakov M, Mann WJ. April 2002 issue of the Southern Medical Journal; abstract online at www.medscape.com/viewarticle/432436.

Who may be affected by these findings?

Gravidas and practitioners contemplating vaginal birth after cesarean (VBAC).

Expert commentary

In the past decade, the issue of VBAC has dominated the obstetrics field. Attempts to lower cesarean-delivery rates have been fueled largely by concerns regarding cost of care. While the promotion of VBAC may save insurance companies money, the risks of a trial of labor cannot be ignored and must be thoroughly examined.

Specific factors estimating the risks or benefits of vaginal birth after cesarean remain controversial.

This study suggests that birth weight and oxytocin use may increase the risk of URD. However, these findings have not been supported by other studies.1,2 Perhaps it is because this retrospective study harbors many limitations. For example, only symptomatic dehiscences were “discovered.” It is likely that a significant number of successful and uncomplicated VBACs sustained some degree of “bloodless dehiscence.” These, however, could not be accounted for unless routine inspection of the lower uterine segment was performed after each delivery. Another limitation of this study is the absence of labor management standards. The authors concluded that use of internal monitoring reduced the likelihood of URD, but this reduction could be a proxy for the more judicious use of uterotonic agents. Further, we do not have data regarding “decision-to-incision” intervals once fetal distress or URD was recognized.

It is important to note that the issue involved here is not one of equivalent risk, but rather, of acceptable risk, which can be determined only by the patient and her physician. At present, I’m inclined to agree with a New England Journal of Medicine editorial suggesting that if the safety of the fetus is the only consideration, elective repeat cesarean (ERC) should be the delivery of choice.3 Clearly, not every patient or clinician will see it this way.

Bottom line

The current study underscores the complexity of this issue. But while its conclusions may not be not unanimously agreed upon, the patient and the practitioner would be well advised to recognize that VBAC does indeed increase the risk of URD. Further, they should note that specific factors estimating the risks or benefits of VBAC remain controversial.

While these matters continue to be debated, facilities need to adopt a plan wherein rapid accomplishment of an emergency cesarean can occur and neonatal resuscitation personnel are immediately available.

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