The 17‑OH progesterone blood test measures 17‑hydroxyprogesterone, a steroid produced by adrenals and ovaries. It’s used to screen and diagnose congenital adrenal hyperplasia (especially 21‑hydroxylase deficiency), evaluate ambiguous genitalia, premature pubic hair, hirsutism or infertility, and to monitor treatment. Levels are often checked in the morning and may be paired with ACTH stimulation or repeat testing for confirmation.

High 17‑hydroxyprogesterone indicates impaired cortisol synthesis, most commonly 21‑hydroxylase congenital adrenal hyperplasia (classical or nonclassical). It causes excess androgens leading to ambiguous genitalia in newborns, rapid childhood growth, early puberty, hirsutism, acne, irregular menses and infertility. Less commonly it reflects adrenal or ovarian tumors or luteal‑phase variation; diagnosis uses ACTH stimulation and genetic testing, treated with glucocorticoids.

Normal 17‑hydroxyprogesterone (17‑OHP) varies by lab and menstrual phase. In adult females it’s typically low in the follicular phase (about 0.1–1.0 ng/mL), rises around ovulation, and is higher in the luteal phase (roughly up to 1–3 ng/mL). Markedly elevated levels suggest congenital adrenal hyperplasia. Always compare results with your lab’s reference range and discuss abnormal values with your clinician.

In PCOS, 17‑hydroxyprogesterone (17‑OHP) is often normal or only mildly elevated. Markedly raised basal or ACTH‑stimulated 17‑OHP suggests non‑classic congenital adrenal hyperplasia (21‑hydroxylase deficiency) rather than PCOS. If results are borderline, an ACTH stimulation test helps clarify the diagnosis; discuss testing and interpretation with your clinician.

Symptoms include high blood pressure and low potassium from excess mineralocorticoids; sexual infantilism—absent or delayed puberty and lack of secondary sexual characteristics; genetic males (46,XY) often have undervirilization or ambiguous genitalia at birth; genetic females (46,XX) typically have primary amenorrhea and lack breast development; fatigue, muscle weakness, low libido, and increased osteoporosis risk from low sex steroids and cortisol.

17-hydroxyprogesterone (17‑OHP) is a steroid intermediate produced mainly by the adrenal glands and a precursor in cortisol and androgen synthesis; it’s measured clinically to screen for congenital adrenal hyperplasia. Progesterone is the principal progestogen from the corpus luteum and placenta, crucial for menstrual cycle regulation and pregnancy support and used therapeutically. 17‑OHP is mainly a diagnostic marker while progesterone has major physiological effects.