Glossary
PCOS terms, in plain language.
31 terms you may meet in an appointment or an article, each with a short definition and a note on why it matters. Search for a word, or filter by category.
Showing all 31 terms
- Symptoms & related conditions
Areas of skin that become darker, thicker, and sometimes velvety, often around the neck, armpits, or groin.
Good to know
It can be associated with insulin resistance, though other causes are possible.
- Symptoms & related conditions
A skin condition involving clogged or inflamed hair follicles, resulting in pimples, blackheads, or other lesions.
Good to know
Persistent acne can occur with PCOS, but acne by itself is a relatively weak indicator of androgen excess.
- Cycles & fertility
The absence of menstrual periods.
Good to know
Long gaps without bleeding warrant clinical evaluation; protecting the uterine lining may be part of care when ovulation is infrequent.
- Hormones & metabolism
A group of hormones, including testosterone, that are present in people of all sexes and contribute to processes such as hair growth and sexual development.
Good to know
Higher androgen activity is common in PCOS, but not everyone with PCOS has elevated levels.
- Cycles & fertility
When an ovary does not release an egg during a menstrual cycle.
Good to know
Bleeding can sometimes occur without ovulation, so having a period does not always confirm that ovulation happened.
- Hormones & metabolism
A hormone produced by cells in developing ovarian follicles; blood levels can help estimate the number of small follicles.
Good to know
In adults, AMH may be used as an alternative to ultrasound when assessing polycystic ovarian morphology, but not as a standalone PCOS test. It is not recommended for diagnosing PCOS in adolescents.
- Diagnosis & treatment
A birth-control pill that contains both estrogen and a progestin.
Good to know
It may help manage irregular cycles, acne, or hirsutism in PCOS; the right formulation depends on health history and individual risks.
- Cycles & fertility
An overgrowth or abnormal thickening of cells in the lining of the uterus.
Good to know
Prolonged infrequent menstrual bleeding can be associated with increased risk; unusual or prolonged bleeding should be assessed by a clinician.
- Cycles & fertility
The lining of the uterus that normally thickens and sheds in response to hormone changes during the menstrual cycle.
Good to know
Irregular or absent ovulation can affect how this lining grows and sheds.
- Symptoms & related conditions
Gradual thinning of scalp hair, commonly around the central part or crown.
Good to know
Hair loss can have several causes; evaluation may include checking for non-PCOS contributors.
- Hormones & metabolism
A pituitary hormone involved in the development of ovarian follicles, which contain immature eggs.
Good to know
FSH results depend on age, cycle timing, and clinical context.
- Symptoms & related conditions
Growth of coarse, darker hair in areas such as the face, chest, or abdomen in a pattern associated with androgen activity.
Good to know
It can be a sign of hyperandrogenism, and its impact on daily life deserves attention even when blood test results are normal.
- Hormones & metabolism
Higher-than-expected androgen levels or physical signs of increased androgen activity, such as excess coarse facial hair.
Good to know
It may be identified through symptoms or blood tests; other possible causes should also be considered.
- Hormones & metabolism
A hormone made by the pancreas that helps glucose move from the bloodstream into cells for energy or storage.
Good to know
The body may produce more insulin to compensate for insulin resistance.
- Hormones & metabolism
A condition in which the body’s cells respond less effectively to insulin, making it harder for the body to regulate blood glucose.
Good to know
It is common in PCOS but is not one of the required diagnostic criteria.
- Diagnosis & treatment
A prescription aromatase inhibitor that temporarily lowers estrogen production and may stimulate ovulation.
Good to know
The 2023 PCOS guideline recommends it as first-line medication for ovulation induction in eligible adults with anovulatory infertility and no other infertility factors.
- Hormones & metabolism
A hormone released by the pituitary gland that helps regulate ovarian function and triggers ovulation.
Good to know
The LH-to-FSH ratio is not required to diagnose PCOS.
- Symptoms & related conditions
A cluster of health risk factors, such as elevated blood pressure, abnormal blood lipids, higher blood glucose, and increased waist circumference.
Good to know
Not every person with PCOS has metabolic syndrome; individual risks should be assessed rather than assumed.
- Diagnosis & treatment
A prescription medicine that reduces glucose production by the liver and improves the body’s response to insulin.
Good to know
It may be considered for metabolic outcomes in PCOS, depending on individual circumstances; gastrointestinal side effects are common.
- Cycles & fertility
Menstrual periods that occur infrequently, often with unusually long gaps between cycles.
Good to know
In adults more than three years after the first period, cycles longer than 35 days or fewer than eight per year can be considered irregular in a PCOS assessment.
- Cycles & fertility
A small, fluid-filled structure in an ovary that contains an immature egg.
Good to know
The small follicles sometimes seen on ultrasound in PCOS are not the same as harmful ovarian cysts.
- Cycles & fertility
The release of an egg from an ovary during the reproductive cycle.
Good to know
Ovulation may be unpredictable in PCOS, so calendar-based fertility predictions may be less reliable.
- Cycles & fertility
An ovarian appearance characterized by a greater number of small follicles and/or increased ovarian volume, assessed using appropriate criteria.
Good to know
PCOM alone does not establish a PCOS diagnosis, and ultrasound is not recommended as a diagnostic criterion in adolescents.
- Diagnosis & treatment
A common hormonal and metabolic condition associated with combinations of irregular ovulation, androgen excess, and characteristic ovarian findings.
Good to know
There is no single test that diagnoses every case. Symptoms and care needs vary widely.
- Symptoms & related conditions
Blood glucose levels that are higher than normal but not high enough to meet diagnostic criteria for diabetes.
Good to know
PCOS is associated with increased risk of impaired glucose regulation; screening options should be discussed with a healthcare professional.
- Diagnosis & treatment
A medicine that acts similarly to the hormone progesterone.
Good to know
A clinician may prescribe a progestin regimen to help manage bleeding or protect the uterine lining when periods are infrequent.
- Diagnosis & treatment
A framework commonly used to diagnose PCOS in adults after excluding other causes. Typically, two of three features are needed: androgen excess, ovulatory dysfunction, or polycystic ovarian morphology.
Good to know
In adults, AMH can sometimes substitute for ultrasound when evaluating ovarian morphology. Adolescents use different diagnostic rules.
- Hormones & metabolism
A protein made mainly by the liver that binds to sex hormones, including testosterone, in the bloodstream.
Good to know
Lower SHBG can increase the proportion of testosterone that is unbound; results are interpreted alongside other tests.
- Diagnosis & treatment
A prescription medicine that blocks some effects of androgens and is sometimes used to treat excess hair growth or acne.
Good to know
Effective pregnancy prevention is important when using anti-androgen medicines because of potential risks to a developing fetus.
- Hormones & metabolism
An androgen hormone made in different amounts by the ovaries, adrenal glands, and testes.
Good to know
Testing testosterone can help assess androgen excess; results need interpretation using appropriate reference ranges.
- Diagnosis & treatment
An imaging examination in which a narrow ultrasound probe is placed in the vagina to view the uterus and ovaries.
Good to know
When appropriate and acceptable to the patient, it can assess ovarian morphology; it is not required for every adult PCOS diagnosis.
Sources
- 2023 International Evidence-based Guideline for the Assessment and Management of PCOS
- ACOG: Polycystic Ovary Syndrome (PCOS)
Educational information only; not medical advice. Definitions are not diagnostic criteria or individualized treatment recommendations.