Revisiting the role of serum progesterone as a test of ovulation in eumenorrheic subfertile women: a prospective diagnostic accuracy study.

Objective: To estimate the prevalence of ovulatory cycles in eumenorrheic subfertile women and compare the diagnostic accuracy of a single ultrasound with serum midluteal progesterone measurement in detecting ovulatory cycles.

Design: Prospective diagnostic accuracy study.

Setting: University-level hospital.

Patient(s): A total of 208 subfertile eumenorrheic women.

Intervention(s): None.

Main Outcome Measure(s): To estimate the prevalence of ovulatory cycles in eumenorrheic women and compare the diagnostic accuracy of a single, well-timed ultrasound scan (index test) with serum progesterone measurement (reference test) by calculating the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive likelihood ratio (LR+) and negative likelihood ratio (LR-).

Result(s): The prevalence of ovulatory cycles among subfertile eumenorrheic women was 92.9% and 99.5% when midluteal serum progesterone level and ultrasound scanning were used as the reference test, respectively. The sensitivity, specificity, PPV, and NPV of ultrasound in identifying ovulatory cycles were 100%, 7.1%, 93.4%, and 100%, respectively. The LR+ and LR- were 1.1 and 0, respectively. The agreement between the ultrasound and serum progesterone was almost perfect (prevalence and bias-adjusted kappa = 0.81.

Conclusion(s): The prevalence of ovulatory cycles in eumenorrheic subfertile women appears to be high. A single well-timed ultrasound can be performed to identify ovulatory cycles during the infertility workup in eumenorrheic women.