Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder, affecting up to 10% of women of reproductive age worldwide. The condition is characterized by hormonal imbalances and reproductive concerns, making it the leading cause of anovulatory infertility. The journey to formally recognizing and naming this disorder spans centuries due to its varied presentation. Tracing its historical path reveals how physicians moved from observing isolated symptoms to defining this cohesive, yet multifaceted, syndrome.
Early Medical Descriptions
Observations of women displaying characteristic PCOS symptoms appeared in medical literature long before the syndrome was formally defined. In 1721, Italian physician Antonio Vallisneri described a young, infertile, moderately obese woman whose ovaries were “larger than normal, bumpy, shiny and whitish, just like pigeon eggs.” This description captured key components: infertility, specific body habitus, and abnormal ovarian morphology.
In the 19th century, more detailed pathological descriptions emerged, separating the condition from general gynecological issues. In 1844, French doctor Achille Chereau described enlarged, elastic ovaries containing many small cysts located on the periphery. These accounts focused primarily on the physical appearance of the ovaries, often referring to them as having “sclerocystic changes.” The physical manifestations were noted centuries ago, though the underlying hormonal cause was not yet understood.
The Stein-Leventhal Discovery
The formal recognition of the collection of symptoms as a distinct syndrome occurred in 1935, thanks to American gynecologists Irving F. Stein, Sr., and Michael L. Leventhal. They presented a report detailing the clinical histories of seven women who shared amenorrhea, excessive hair growth (hirsutism), and subfertility.
Crucially, the doctors linked these clinical symptoms to a specific surgical finding: bilaterally enlarged, polycystic-appearing ovaries. The ovaries had a thickened outer capsule (tunica albuginea) and were filled with numerous small, fluid-filled sacs. This systematic connection between clinical presentation and pathological ovarian appearance allowed them to propose a unified condition, initially named the Stein-Leventhal syndrome.
Stein and Leventhal hypothesized the syndrome resulted from an underlying endocrine dysfunction. Their primary treatment involved ovarian wedge resection, a surgical procedure where a portion of the ovary was removed. They found this procedure often led to the resumption of regular menstrual cycles and increased the likelihood of pregnancy, solidifying the link between ovarian morphology and clinical symptoms. This landmark publication marked the beginning of modern research into the disorder.
Decades of Diagnostic Refinement
Following its formal discovery, the understanding of the syndrome broadened, moving beyond the initial focus on ovarian morphology and surgical treatment. Research from the 1950s through the 1970s focused on the neuroendocrine background, establishing PCOS as a complex disorder of the endocrine system rather than a structural problem with the ovaries.
This shift accelerated in the 1980s and 1990s as advanced biochemical testing allowed researchers to measure specific hormones. It became clear that elevated levels of androgens (hyperandrogenism) were a fundamental component of the disorder. This hormonal imbalance drives external symptoms like hirsutism and acne, and disrupts normal ovulation.
A major turning point was the realization that insulin resistance was deeply connected to the condition. Insulin resistance causes the pancreas to produce excess insulin, which stimulates the ovaries and adrenal glands to produce more androgens. This established PCOS as a metabolic disorder with gynecological manifestations. The first formal attempt to create standardized diagnostic criteria occurred in 1990 at a National Institutes of Health (NIH) conference, defining the syndrome by the mandatory presence of both hyperandrogenism and chronic anovulation.
Current Understanding of PCOS
The contemporary medical definition of PCOS reflects the expanded understanding of its endocrine and metabolic complexity, moving away from the strict criteria of the past. The most widely accepted diagnostic framework is the Rotterdam Criteria, established by a 2003 consensus workshop. This framework defines PCOS by the presence of at least two out of three specific features: oligo- or anovulation, clinical or biochemical signs of hyperandrogenism, and polycystic ovarian morphology (PCOM) on ultrasound.
The Rotterdam Criteria significantly broadened the definition compared to the earlier NIH criteria, recognizing that not all women present with the characteristic polycystic ovaries. The inclusion of PCOM as only one of three required features acknowledges the disorder’s heterogeneity. For instance, a woman can be diagnosed with PCOS if she has irregular periods and hyperandrogenism, even if her ovaries appear normal on an ultrasound.
Furthermore, the term “polycystic ovaries” is now understood to be a misnomer, as the fluid-filled sacs are not true cysts but rather immature follicles arrested in development. The focus of diagnosis has shifted to a combination of clinical symptoms, hormonal testing, and ultrasound imaging. This evolution from a surgical observation to a complex, multi-system diagnosis illustrates the continuous refinement of medical knowledge.