The size of the cervix and its relationship with age and parity

The aim of this study was to determine whether cervical diameter changes with age, parity or hormonal status, as we postulate that the cervical size can influence pelvic organ prolapse quantification (POPQ) staging, as apical stage 0 assumes a cervical diameter of ≤2 cm. We reviewed all hysterectomies performed at a single university-affiliated hospital and compared ex vivo cervical diameter based on parity, menopausal status and hormonal exposure. Specimen results were available for 127 women, mean age 48 years (rage 24-89), half were parous. Most (83%) surgical indications were benign. Of the 77 women whose menopausal status was known, 25 were postmenopausal. The mean cervical diameter was greater in women <55 years [3.5 cm, 95% confidence interval (CI) (3.4-3.6) vs 2.8 cm 95%CI (2.7-2.9)]. Parity was also associated with greater cervical diameter [3.4 cm, 95%CI (3.2- 3.6) vs 3.0 cm 95%CI (2.7-3.3)]. Only three women had a cervix ≤2 cm. The cervical diameter is considerably larger in younger and parous women. Consequently, its size may, conceptually, affect the apical staging of POPQ. Such misclassification could obscure identification and affect interpretation of studies evaluating the natural history or outcomes following surgical treatment of prolapse.