Cervical elongation is common in women with uterine pelvic organ prolapse (POP) and may influence surgical planning and recurrence risk, yet its definition and clinical assessment remain inconsistent. We hypothesised that the POP Q C–D distance provides an accurate clinical estimate of true cervical length and can reliably detect cervical elongation when validated against postoperative anatomic measurements on hysterectomy specimens. The aim of this study was to evaluate the agreement between POP Q C–D–derived cervical length and measured cervical length, to compare corpus to cervix ratios in women with and without POP, and to determine an optimal POP Q C–D cutoff for diagnosing cervical elongation.

We conducted a cross sectional diagnostic accuracy study in women undergoing hysterectomy for symptomatic apical POP (stage 2–4) or benign non prolapse indications at two tertiary centres in 2025. Preoperatively, all participants underwent standardised POP Q examination by trained clinicians, and POP Q–based cervical length was calculated as the absolute C–D distance. Immediately after hysterectomy, uterine corpus and cervical lengths were measured on opened specimens with a ruler, corpus to cervix ratios were calculated, and cervical elongation was graded from 0 to III. Statistical analyses included correlation and Bland–Altman agreement between POP Q and anatomic cervical length, multivariable linear and logistic regression for determinants of elongation, and ROC analysis with Youden index to identify the optimal C–D cutoff.

A total of 150 women were included: 75 with POP and 75 undergoing hysterectomy for non prolapse indications. POP patients were older, had higher gravidity and parity, greater BMI, and longer postmenopausal duration than controls (all p < 0.001). POP Q C–D–derived cervical length showed a strong correlation with postoperative anatomic cervical length (r = 0.93), with POP Q slightly underestimating true length by a mean of −0.35 cm (p < 0.001). Women with POP had longer cervices, shorter corpora, and markedly lower corpus to cervix ratios than controls (all p < 0.001), consistent with disproportionate cervical elongation. In multivariable models, POP Q derived cervical length was the only independent predictor of anatomic cervical length (R² = 0.87), and together with age was associated with high grade cervical elongation. ROC analysis demonstrated excellent diagnostic performance of POP Q C–D for cervical elongation (AUC 0.95), with an optimal cutoff of 4.5 cm yielding sensitivity 74.6% and specificity 100%.

Our findings demonstrate that the POP Q C–D distance provides a robust and clinically feasible proxy for true cervical length in women with advanced apical POP. The small systematic underestimation observed is unlikely to be clinically important given the high linear agreement and strong predictive performance across elongation grades. The pronounced differences in corpus to cervix ratio between POP and non POP hysterectomy patients support the concept that prolapse is characterised not only by apical descent but also by disproportionate cervical elongation. However, specificity estimates for the 4.5 cm cutoff should be interpreted with caution because of the limited number of non elongated cervices, and the study population was restricted to older women with relatively advanced prolapse managed in tertiary centres.

POP Q C–D distance is an accurate, simple bedside measure that closely reflects anatomic cervical length and effectively identifies cervical elongation in women undergoing surgery for apical POP. Incorporating POP Q–based cervical length assessment into routine preoperative evaluation may improve risk stratification, inform decisions regarding uterine preserving versus extirpative procedures, and guide the need for concomitant cervical shortening techniques. Further validation in broader, less selected clinical populations and across different care settings is warranted to confirm the generalisability of these findings.