X-ray Pelvimetry Has No Impact on the Outcomes of Trial of Labor after Cesarean Delivery: A Retrospective Single-center Study.

Few studies have examined the relationship between pelvic size and the success or failure of trial of labor after cesarean delivery (TOLAC). Here we aimed to determine whether pelvic size and morphological data obtained from radiography contribute to the first successful TOLAC. This retrospective single-center observational study enrolled pregnant women who underwent TOLAC between 2010 and 2021. The results of X-ray pelvimetry data, including obstetric conjugate (OC), transverse diameter of the pelvic inlet (TD), anteroposterior diameter of the pelvic inlet (APD), shape of the pelvic inlet, and other obstetrical clinical data, were compared between the success and failure groups. Seventy-five patients in successful group after excluding 35 patients with previous successful TOLAC, and 21 patients in failure group were eligible. The failure group had a higher rate of previous cesarean sections due to failed labor trials (p = 0.042) and heavier newborns (p = 0.014). OC, TD, and APD on X-ray pelvimetry did not differ significantly between the two groups nor did the shape of the pelvic inlet affect the success rate for TOLAC. The generalized linear model identified a history of failed trials of labor as a significant predictor of failed TOLAC (odds ratio, 0.26; 95% confidence interval 0.071-0.923; p = 0.037), whereas no pelvimetric parameters were found. Pelvic size and morphological findings have no discernible impact on the outcomes of TOLAC. The universal application of X-ray pelvimetry in all women attempting TOLAC may not have significant clinical relevance.