Reply to: Cesarean scar defect-A rising concern or a physiological healing process?

Abstract

Sir, We greatly appreciate the letter from Drs. Levin and Rottenstreich1 as well as their interest in and comments on our study.2 First, we respectfully point out that our study included women who had undergone either elective or non-elective cesarean delivery. We discussed the limitation of our approach in detecting cesarean scar defects (CSD) postpartum and the timing of transvaginal ultrasound scanning in the article. Compared with the reference standard, contrast enhanced sonohysterography, our prevalence and size of CSD as determined by transvaginal ultrasound may have been slightly underestimated. However, we strongly believe that the findings are sufficient for risk factor analyses. As to timing for initial CSD evaluation, the recommended minimal inter-pregnancy interval could not serve as an optimal timeframe for CSD screening; neither could the 6-12-month timeframe used in previous studies. As there is a lack of longitudinal follow-up studies concerning uterine scarring after cesarean section and CSD, the optimal earliest time-point for assessment remains unknown and guideline establishment would be of great benefit for both early warning of CSD and timely intervention. Our study continuously followed women to evaluate the diagnostic value of screening at 6 weeks and sought to determine a timeframe that was optimal for routine assessment of women who had undergone cesarean section. We believe that the Dutch Trial Register (NTR5480)3 will provide acceptable timeframes for screening of CSD. We considered how antibiotic consumption and postpartum body temperature together influence CSD pathogenesis and that antibiotic administration can indeed be protective. We analyzed both postoperative morbidity and CSD occurrence; however, confounding factors deemed the results insignificant. Data obtained from the subfebrile patient group (temperature 37.5-38.0°C) clarified the benefit of antibiotic administration and its subsequent influence on body temperature. We found that subfebrile postpartum women were in greater danger of suffering CSD than febrile patients. Levin et al criticized our clinically logical assumptions based on a certain interpretation of a basic science study.4 On the contrary, that study concluded that calcium-channel blockers can thin and weaken hypertrophic scars. Such findings are consistent with our hypothesis. Healing of uterine incisions, however, is influenced by a variety of factors, the most important of which are dynamic globular muscular contractions. Uterine scarring is therefore much more complicated than dermatologic hypertrophic scarring. Platelet structure and count5 during pregnancy as well as fibrinogen concentration6 were also considered in our work. We set 4.5 g/L as a cut-off point based on data from previous literature as almost all studies considering fibrinogen concentration at around 35-40 weeks of gestation set similar cut-off points. Ultimately, our findings are based on evaluation of data obtained from a large sample size and logistic regression analysis. Not only did we report on the CSD prevalence in China but we also detailed a number of interesting and important CSD risk factors for the first time. Our study raises a much-needed concern for CSD, but further research that builds upon the findings from our present cohort will provide an even better understanding of the natural course of CSD formation and methods of prevention.