Development of a Risk Screening Tool for Cephalopelvic Disproportion (CPD) in Pregnant Women at Ranong Hospital

Abstract

     This study aimed to develop a risk screening tool for Cephalopelvic Disproportion (CPD) in pregnant women, determine an appropriate cut-off point using ROC curve analysis, and evaluate the tool's performance via sensitivity, specificity, and area under the curve (AUC). A experimental research conducted between 2022 and 2024 across three phases. Phase 1 retrospectively analyzed 399 women who underwent cesarean section due to CPD (out of all deliveries during the study period), using logistic regression to identify risk factors. Phase 2 developed the screening tool by assigning weighted scores based on odds ratios, with content validity assessed by five experts. Phase 3 prospectively tested the tool in two rounds (n=229 and n=114).

     Phase 1 identified four statistically significant risk factors (p<0.05): primigravida (OR=3.45), estimated fetal weight ≥3,500 g (OR=2.87), fundal height ≥35 cm (OR=2.23), and gestational weight gain ≥15 kg (OR=1.89). Two additional factors were retained for clinical relevance: maternal height <150 cm and maternal age <19 or ≥35 years. These six factors formed the screening tool, with a maximum score of 8.5 and CVI = 0.92. Round 1 testing at the initial cut-off of 2.5 showed very low sensitivity (32.35%). ROC curve analysis and Youden's Index were used to revise the cut-off to 1.5. Round 2 testing (n=114) at cut-off 1.5 showed sensitivity 66.67%, specificity 59.26%, PPV 40.00%, NPV 81.36%, accuracy 61.40%, and AUC = 0.7153 (95% CI: 0.6134–0.8172), indicating fair-to-good performance per Mandrekar's (2010) criteria.