Amenorrhea is considered a type of abnormal menstrual bleeding characterized by the unexpected absence of menstrual bleeding, lasting three months or longer. Menstrual bleeding typically happens approximately once a month when blood and endometrial tissue, or tissue lining the inside of the uterus, sheds from the uterus through the vagina. Menstruation is expected to stop with pregnancy, breastfeeding, and menopause, or the natural cessation of the menstrual cycle at an older age. However, women may also experience amenorrhea because of an underlying health condition, including low body weight or polycystic ovarian syndrome, that may complicate fertility and contribute to decreased quality of life. According to the American College of Obstetricians and Gynecologists, one in twenty-five women experience amenorrhea as a menstrual disorder within their lives at times.

In 1935, US-based physicians Irving Freiler Stein and Michael Leo Leventhal published “Amenorrhea Associated with Bilateral Polycystic Ovaries,” hereafter “Amenorrhea,” in the American Journal of Obstetrics and Gynecology based on their clinical experience with seven female patients. In their article, Stein and Leventhal report finding a correlation between a lack of menstruation for a prolonged period, or amenorrhea, in the women and the presence of bilateral polycystic ovaries, in which cysts form in both ovaries. Stein and Leventhal theorize that such cysts form due to hormonal imbalances, which makes their presence indicative of an endocrine, or hormonal, disorder. That explanation contested a widely held belief at the time that inflammation caused amenorrhea. “Amenorrhea” was one of the first publications to propose a hormonal explanation for bilateral polycystic ovaries and to describe the cluster of symptoms that became the basis for diagnosing what later became known as polycystic ovarian syndrome, or PCOS, an endocrine disorder that affects five to eleven percent of women globally per year.