Prevalence of conditions causing chronic anovulation and the proposed algorithm for anovulation evaluation

This study investigated the prevalence of disease-causing chronic anovulation and proposes a logical investigation flowchart to facilitate diagnosis in women presenting with chronic anovulation.

The cross-sectional retrospective study was performed using 293 reproductive-aged women who were diagnosed with chronic anovulation at the Gynecologic Endocrinology Unit, Faculty of Medicine, Chiang Mai University between January 2008 and December 2012. The demographic data, laboratory investigations and diagnoses were collected.

Among 293 patients recruited into the study, the common causes of anovulation were polycystic ovary syndrome (PCOS) (73.4%), prolactin disorder (13.3%) and unexplained chronic anovulation (7.5%). The less common causes were thyroid disorders, congenital adrenal hyperplasia, adrenal tumors and Cushing's disease. There was a strong positive association between the levels of 17-hydroxyprogesterone and/or dehydroepiandrosterone sulfate with the levels of testosterone and androstenedione. The sensitivity and specificity of serum luteinizing hormone to accurately diagnose PCOS were 29.38% and 55.56% (P = 0.03). The luteinizing hormone/follicle-stimulating hormone ratio ≥ 3 had a sensitivity and specificity at 18.56% and 92.86% (P = 0.03) for PCOS diagnosis.

Serum androstenedione, testosterone, thyroid-stimulating hormone, prolactin levels and pelvic ultrasonography should be included in the initial investigations for anovulation. The 17-hydroxyprogesterone and dehydroepiandrosterone sulfate levels can be used for secondary anovulation evaluations.