Polycystic Ovary Syndrome (PCOS) is a common hormonal and metabolic condition that affects women of reproductive age. Identifying PCOS is not accomplished with a single test but involves a comprehensive evaluation. This diagnostic process is systematic, integrating a patient’s symptoms, physical findings, and specific laboratory results to build a complete clinical picture. The purpose of this multi-step approach is to arrive at an accurate diagnosis by carefully considering all evidence.
Initial Consultation and Symptom Review
The evaluation for PCOS begins with a conversation between the patient and a healthcare provider, often an endocrinologist or a gynecologist. This discussion focuses on the patient’s medical and family history. The provider will ask detailed questions about menstrual patterns, noting irregularities such as infrequent periods (oligomenorrhea) or the complete absence of periods (amenorrhea), which suggest ovulatory dysfunction. The provider will also inquire about any family history of PCOS, diabetes, or fertility challenges.
Following the medical history review, a physical exam is conducted to look for visible signs of the condition. The primary focus is on identifying clinical evidence of hyperandrogenism, which is a state of elevated androgen (male hormone) levels. This can manifest as hirsutism, a pattern of excess hair growth on the face, chest, and back. Other signs include persistent acne beyond the teenage years and androgenic alopecia, a specific type of hair thinning on the scalp.
During this physical assessment, the provider will also measure blood pressure and body mass index (BMI). Skin may be examined for acanthosis nigricans, which are darkened, velvety patches of skin that can indicate insulin resistance, a metabolic issue often linked to PCOS.
Hormonal and Metabolic Blood Tests
A series of blood tests are ordered to measure specific hormonal and metabolic markers. These tests provide biochemical evidence that helps confirm or rule out PCOS. The blood work is performed in the early part of the menstrual cycle, if cycles are present, to ensure the accuracy of hormone level readings.
The hormonal panel focuses on androgens and the hormones that regulate ovulation. Total and free testosterone levels are measured, which are often elevated in women with PCOS. Levels of dehydroepiandrosterone sulfate (DHEAS), another androgen produced by the adrenal glands, may also be assessed. Tests for Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) are performed, as the ratio of LH to FSH is often elevated, which can interfere with normal ovulation.
Metabolic testing is also performed, as PCOS is closely linked to insulin resistance. An oral glucose tolerance test or measurements of fasting glucose and fasting insulin can reveal how the body processes sugar. Even with normal blood glucose, elevated insulin levels can point to underlying insulin resistance, a condition where cells do not respond effectively to insulin. This metabolic disruption can prompt the ovaries to produce excess testosterone. A lipid panel to check cholesterol levels may also be included to assess cardiovascular risk.
Pelvic Ultrasound Examination
An imaging study, often a transvaginal ultrasound, is part of the evaluation to look for polycystic ovarian morphology (PCOM). A transvaginal ultrasound is the preferred method, as it uses a small probe placed in the vaginal canal to produce high-resolution images of the pelvic organs. This technique provides a clearer and more detailed view of the ovaries compared to a transabdominal ultrasound.
During the ultrasound, the clinician examines both the size of the ovaries and the number of follicles they contain. An ovarian volume greater than 10 cubic centimeters is one potential indicator of PCOM. The “cysts” commonly associated with PCOS are not true cysts but rather small, immature egg sacs called antral follicles that have not matured to the point of ovulation.
The criteria for identifying polycystic ovarian morphology have evolved with advancements in ultrasound technology. Current international guidelines suggest a threshold of 20 or more follicles, each measuring 2-9 mm in diameter, in at least one ovary to define PCOM. It is important to note that the presence of PCOM alone is not sufficient for a diagnosis, as many women without PCOS may have similar ultrasound findings.
Diagnostic Criteria and Differential Diagnosis
The most widely accepted framework for diagnosis is the Rotterdam criteria. To be diagnosed with PCOS under these guidelines, an individual must meet at least two of the three following conditions: irregular periods indicating ovulatory dysfunction, clinical or biochemical signs of high androgens, and polycystic ovaries seen on an ultrasound. This framework allows for the diagnosis of different presentations of the syndrome. For instance, a person with irregular periods and high androgen levels can be diagnosed without an ultrasound, while someone with high androgens and polycystic ovaries but regular periods could also meet the criteria.
The diagnostic process involves ruling out other medical conditions that can present with similar symptoms, which is known as a differential diagnosis. For example, thyroid disorders can cause menstrual irregularities, so a blood test for thyroid-stimulating hormone (TSH) is performed. Other conditions that must be excluded include hyperprolactinemia (high levels of the hormone prolactin) and non-classic congenital adrenal hyperplasia, an adrenal gland disorder that can also cause high androgen levels.