Comparison of transabdominal versus transvaginal ultrasound to measure thickness of the lower uterine segment at term

Abstract

Background: The rising global rates of cesarean sections (CS) and pregnancies with CS history necessitate the assessment of uterine scar integrity, potentially using transabdominal or transvaginal ultrasounds as a predictive tool.
Aim: To compare the accuracy and utility of transabdominal and transvaginal ultrasound in measuring lower uterine segment (LUS) thickness at term.
Materials and Methods: We conducted a thorough search on Google Scholar, PubMed, Embase, and Cochrane Library. The investigation utilized both text terms and medical subject headings, such as LUS Thickness, (CS), Transabdominal Ultrasound (TAS), Transvaginal Ultrasound (TVS), Scar Dehiscence, Rupture of uterus, Vaginal Birth following Cesarean, Vaginal Birth After Cesarean (VBAC). Also, we conducted a thorough investigation on ClinicalTrials.gov and examined the references cited in selected materials and reviews to discover any more pertinent observational research.
Results: This meta-analysis incorporated data from 9 studies involving 1,789 patients to assess the differences in lower uterine segment (LUS) thickness measured by (TAS) and (TVS). The studies included participants aged eighteen to 44 years, with a BMI range of 20.7 to 50.4 kilogram/metrer² and gestational ages from 36 to 40 weeks. Our combined analysis revealed a statistically significant variance in LUS thickness between the groups (Z = 4.42, P < 0.0001), highlighting the potential of ultrasound measurement techniques in predicting uterine scar complications.
Conclusion: The findings support the clinical use of LUS measurement, particularly via transvaginal sonography (TVS), as valuable tool in guiding delivery decisions, especially for those considering a trial of labor after cesarean (TOLAC).