Abstract
Introduction
Whether there is an association between residual myometrial thickness (RMT) after cesarean section (CS) and the risk of uterine rupture (UR) or uterine scar dehiscence at the subsequent delivery has been sparsely investigated.
Materials and methods
Our cohort included 149 women with a first CS in whom we measured RMT by transvaginal ultrasonography 6–15 months after their delivery. We did a follow-up study on delivery outcomes in the women’s subsequent births. The exposure was scar measurements in the non-pregnant uterus, and the primary outcome was a diagnosis of UR or dehiscence. We calculated likelihood ratios (LRs) with 95% confidence intervals of having UR or dehiscence with a thin RMT (<3 mm).
Results
Among the 149 women, 39 had a repeat CS (14 scheduled and 25 unscheduled procedures), and within these, we found one woman with UR and five women with uterine dehiscence. The proportion of women with a thin RMT was significantly higher among cases (4/6) than in controls (4/33); the LR was 5.5 (95% CI 1.9–16.2).
Conclusions
The results suggest a significant association between a thin RMT as measured by transvaginal ultrasonography in the non-pregnant uterus after a first scheduled CS and the risk of UR or dehiscence at a subsequent delivery.
Acknowledgments
The authors would like to thank Professor P. Steer for valuable comments on the study.
Disclosure statement
No potential conflict of interest was reported by the author(s).