Causes of Secondary Amenorrhea: A report of 437 cases in Thailand

Abstract

Objectives: The aim of this study was to determine the prevalence of etiologic causes of secondary amenorrhea in Thailand.
Materials and Methods: A retrospective study was performed using 437 complete medical records of women with secondary amenorrhea who visited the Gynecologic Endocrinology clinic, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand from April 1999 to October 2020
Results: At the time of registration at our clinic, the patients had an average age of 28.7 ± 7.7 years. The median duration of amenorrhea was 8 months (range three months to 228 months). The majority of patients were nulliparous (70%). The average body mass index (BMI) was 25.2 ± 6.7 kg/m2. More than half of all patients were overweight (11.2%) and obese (42.6%). Patients with polycystic ovary syndrome (PCOS) had the highest BMI. The four most common causes of secondary amenorrhea were PCOS (30.2%), anovulation (27.2%), hyperprolactinemia (9.8%), and premature ovarian insufficiency (9.2%). Other etiologies were diverse and less frequent. Two thirds of etiologies of secondary amenorrhea were in compartment four (67.5%). The prevalence of causes of secondary amenorrhea in compartment two (9.2%) and three (10.1%) was similar. The uterine cause and outflow tract obstruction was the least common cause of secondary amenorrhea (8.0%) of all four compartments. Postpill amenorrhea was found in 6.4% of patients. Meanwhile, thyroid disorder was the cause of secondary amenorrhea in 5% of patients.
Conclusion: The most common causes of primary and secondary amenorrhea were different. The most common cause of secondary amenorrhea in this study was PCOS. Further studies are required to determine the difference in causes of secondary amenorrhea in different nations.