Association Between Female Bony Pelvimetry Using Magnetic Resonance Imaging and Cesarean Delivery due to Cephalopelvic Disproportion

Purpose: To analyze the difference in bony pelvimetry using magnetic resonance imaging (MRI) in women who delivered vaginally and those who underwent cesarean section (CS) due to cephalopelvic disproportion (CPD).Methods: This retrospective case-control study enrolled Korean women who gave birth to their first child between 37 and 42 weeks of pregnancy and underwent pelvic MRI between January 2014 and June 2020. These women were classified into 3 groups: vaginal delivery (VD), CS due to CPD (CPD-CS), and CS due to reasons other than CPD (Other-CS). In MRI images, true conjugate (TC), obstetric conjugate (OC), mid anterior-posterior (AP) distance (MAD), outlet AP distance (OAD), ischial spine distance (ISD), ischial tuberosity distance (ITD), and pubic angle (PA) were measured.Results: In total, 392 women were enrolled. There were no significant differences in maternal height and body mass index at birth among the 3 groups. The ISD was statistically different between the VD group (106.2±6.4 mm) and the Other-CS group (110.4±8.8 mm) (p=0.014). After multiple regression analysis, short ISD (adjusted odds ratio [aOR], 0.92; 95% confidence interval [CI], 0.87-0.97; p=0.002), short MAD (aOR, 0.95; 95% CI, 0.89-0.99; p=0.047), and short ITD (aOR, 0.95; 95% CI, 0.91-0.99; p=0.019) were significantly associated with CS due to CPD.Conclusion: Short ISD, MAD, and ITD, measured using MRI, are important parameters that can predict CS due to CPD. The accumulation of related research could promote the development of an excellent imaging method in terms of cost-effectiveness. Thus, it may be possible to establish a method to reduce obstetric and perinatal complications due to dystonia.