Progesterone Challenge Test for Amenorrhea Evaluation
Administer medroxyprogesterone acetate 5–10 mg daily for 5–10 days, norethindrone acetate 5 mg daily for 5–10 days, or micronized progesterone 200–300 mg daily for 10 days at bedtime, then observe for withdrawal bleeding within 2–14 days after the last dose. 1
Test Protocol and Dosing Options
The Endocrine Society guideline provides three equivalent regimens for the progesterone challenge test 1:
- Medroxyprogesterone acetate: 5–10 mg orally daily for 5–10 days 1
- Norethindrone acetate: 5 mg orally daily for 5–10 days 1
- Micronized progesterone: 200–300 mg orally daily for 10 days 1
For micronized progesterone specifically, take the dose at bedtime in a standing position with a full glass of water because drowsiness, dizziness, blurred vision, difficulty speaking, and difficulty walking can occur within hours of administration. 2
Some clinicians start with a shorter 5-day course and repeat in a few weeks if no withdrawal bleed occurs, as progestins are not well tolerated by all patients. 1
Interpretation of Results
Positive Test (Withdrawal Bleeding Occurs)
Withdrawal bleeding within 2–14 days after completing progesterone indicates adequate endogenous estrogen production and a patent outflow tract. 1, 3
- This response suggests the patient has sufficient estrogen exposure to prime the endometrium 1
- The amenorrhea is likely due to anovulation rather than estrogen deficiency 3
- In the context of functional hypothalamic amenorrhea (FHA) versus polycystic ovary syndrome (PCOS), a positive test provides additional information about estrogen status, particularly when there is clinical overlap between these conditions 1
- Research shows that endogenous estradiol concentrations correlate with bleeding response—women who bleed have significantly higher baseline estradiol levels 4, 5
Negative Test (No Withdrawal Bleeding)
Absence of withdrawal bleeding indicates either outflow tract obstruction or insufficient endometrial estrogen exposure (hypoestrogenism). 1, 3
When no bleeding occurs 1:
- Perform pelvic ultrasound to assess endometrial thickness and confirm Müllerian tract integrity 1
- Endometrial thickness on ultrasound helps distinguish between inadequate estrogen priming versus anatomic obstruction 1
- If ultrasound findings are equivocal, MRI may be necessary to confirm Müllerian tract integrity 1
- A negative test with a competent outflow tract indicates hypoestrogenic amenorrhea; proceed to measure serum FSH and LH to distinguish ovarian failure from hypothalamic/pituitary dysfunction 3
Clinical Context and Predictive Value
The progesterone challenge test serves as both a diagnostic tool and a method to time blood sampling for hormonal evaluation. 6
- In secondary amenorrhea, the test helps differentiate between adequate versus inadequate estrogen states 3, 6
- Micronized progesterone 300 mg induces withdrawal bleeding in 90% of women with adequate estrogen, compared to only 29% with placebo 5
- The 200 mg dose produces bleeding in 58% of women 5
- Bleeding response cannot be reliably predicted from baseline estradiol and progesterone concentrations alone 5
- In women with oligomenorrhea or amenorrhea, progesterone can be used to induce withdrawal bleeding in order to time early follicular phase blood sampling for diagnostic purposes 6
Important Safety Considerations
Micronized progesterone capsules contain peanut oil and are contraindicated in patients with peanut allergy. 2
Always rule out pregnancy before administering progesterone. 2
Additional contraindications include 2:
- Unusual vaginal bleeding of unknown cause
- Current or history of certain cancers (breast, uterine)
- History of stroke, heart attack, or blood clots
- Current or history of liver problems
- Known allergy to progesterone
Common side effects of micronized progesterone include extreme drowsiness, dizziness, blurred vision, difficulty speaking, difficulty walking, and feeling abnormal—these symptoms typically occur during initial therapy and are the reason for bedtime dosing. 2
Diagnostic Algorithm After Challenge Test
If Withdrawal Bleeding Occurs:
- Diagnose anovulatory amenorrhea with adequate estrogen 3
- Investigate causes of anovulation: PCOS, mild FHA, thyroid dysfunction, hyperprolactinemia 3
- Prescribe cyclic progesterone (same dosing regimen every 1–3 months) to prevent endometrial hyperplasia 1, 3