Is scar tenderness a reliable sign of scar complications in labor?

Abstract

Background: Cesarean section has come a long way from being a risky & restrictive surgery to one that is safe and quick. Due to a rise in the rates of primary caesarean section globally, repeat cesarean section has also become very common. The chief concern during labor with scarred uteri is that of scar rupture which can have devastating fetal and maternal consequences, including mortality. Several studies monitoring for the features of scar rupture like abnormal cardiotocography (CTG), severe abdominal pain persisting between contractions, acute onset scar tenderness, hematuria or abnormal vaginal bleeding, maternal tachycardia or shock, cessation of uterine activity and loss of station of the presenting part exist with the exception of scar tenderness which has not been evaluated separately in any study. The present prospective observational study was undertaken in a tertiary care hospital to evaluate the sensitivity and specificity of scar tenderness as a sign of scar complications in labor.

Methods: 78 women with one previous cesarean delivery in spontaneous labor at term undergoing trial of scar were monitored for progress of labor and observed for vaginal bleeding, scar tenderness, maternal pulse and blood pressure every 30 minutes. Scar tenderness was elicited by pressing below and behind the pubic symphysis in between uterine contractions while engaging the woman in conversation and noting for a visible wince. Fetal heart rate auscultation was done as per protocol. Trial of scar was terminated for scar tenderness, unexplained maternal tachycardia, fresh vaginal bleeding, fetal heart rate abnormalities and non-progress of labor.

Results: The sensitivity and specificity of scar tenderness as a predictor of scar complications was 92.3% and 3.8%, while accuracy was 33.3%. The likelihood ratio of a positive sign of scar tenderness being associated with scar complications in labour is 1.48. Maternal tachycardia was not a significant predictor of scar complications in labour (p value=0.2). Past history of D&E has relative risk of 2.85 for scar complications.

Conclusions: Scar tenderness is a sensitive sign of scar complications and should continue to be elicited for all women undergoing trial of labor after previous caesarean.