Strengths and Limitations
This study also had some limitations. First, some patients were lost to
follow-up. Second, its single-center structure and provision of limited
information on abnormal uterine bleeding symptoms prevented the
long-term assessment of symptoms such as PMB. However, there were
several strengths, including the implementation of a randomized
controlled design, the use of one tertiary center entailing the same
surgical techniques, the stipulation that all patients were undergoing
their first CD, the double-blinded assessment procedure in which neither
the physicians nor patients had knowledge about whether single- or
double-layer closures were used, the examination of patients via SIS by
two experienced sonographers, and the practice of waiting at least six
months before conducting patient follow-ups, thus allowing sufficient
tissue healing. Further, the sample size was calculated via power
analysis based on niche and with a broad number of patients with 90%
power. In addition, previous studies assessed CD scar defects only
during the first three postoperative months or via transabdominal/TV
USG, while many only presented RMT or niche results. As such, this study
took niche and myometrial thickness measurements with multiple planes
after at least six months based on the European Society for
Gynaecological Endoscopy (ESGE) guidelines. Finally, previous studies
accepted niche presence beginning at depths of 1mm, while this study
required at least 2mm, thereby producing more specific results.