Absence of menses for ≥3 months (regular cycles) or ≥6 months (irregular cycles) in a previously menstruating woman.
Also known as: secondary amenorrhea, missed menses, absent menses
Overview
Cessation of menstruation for at least 3 consecutive months in a woman with previously regular cycles, or 6 months in a woman with previously irregular cycles.
Epidemiology
Affects ~3-4% of reproductive-age women. Pregnancy is by far the most common cause; pathologic causes include PCOS (most common pathologic), hypothalamic amenorrhea, hyperprolactinemia, thyroid disease, and primary ovarian insufficiency.
Try two board-style Secondary Amenorrhea questions
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Question 1EndocrineMedium
A 35-year-old female has 6 months of amenorrhea, vaginal dryness, hot flashes, and mood changes. Follicle-stimulating hormone (FSH) is 78 IU/L, luteinizing hormone (LH) is 52 IU/L, and estradiol is 18 pg/mL. Anti-ovarian antibodies are positive. Which of the following is the most likely diagnosis?
AAsherman syndrome
BHyperprolactinemia
CPolycystic ovary syndrome
DHypothalamic amenorrhea
EPrimary ovarian insufficiency
Reveal answer & full explanation
Correct answer: E — Primary ovarian insufficiency
AAsherman syndrome
BHyperprolactinemia
CPolycystic ovary syndrome
DHypothalamic amenorrhea
EPrimary ovarian insufficiency✓
Why Primary ovarian insufficiency is correct
Primary ovarian insufficiency (POI) is defined as follicle-stimulating hormone (FSH) >25 IU/L on two occasions ≥4 weeks apart before age 40, with menstrual irregularity.
High follicle-stimulating hormone (FSH)/luteinizing hormone (LH) plus low estrogen = hypergonadotropic hypogonadism.
Distinguish from hypothalamic amenorrhea: low FSH/LH plus low estrogen (hypogonadotropic hypogonadism).
Anti-ovarian antibodies suggest an autoimmune etiology.
Treatment: hormone replacement therapy (HRT) until average menopausal age (51) to prevent osteoporosis, cardiovascular disease, and cognitive decline.
Spontaneous pregnancy remains possible in 5–10% of cases.
Why the others are wrong
Asherman syndrome — intrauterine adhesions (usually post-instrumentation) cause amenorrhea with normal FSH/LH and estradiol, and produce no hot flashes or vaginal dryness since estrogen is preserved.
Polycystic ovary syndrome — presents with oligomenorrhea plus hyperandrogenism and an elevated LH:FSH ratio with normal or high estradiol, not the high FSH/LH with low estrogen and hypoestrogenic symptoms seen here.
Hypothalamic amenorrhea — causes hypogonadotropic hypogonadism with low FSH/LH and low estradiol, the opposite of the markedly elevated gonadotropins in this patient.
Hyperprolactinemia — a common, treatable cause of secondary amenorrhea with hypoestrogenic symptoms, but elevated prolactin suppresses GnRH pulsatility and yields low or inappropriately normal FSH/LH, not the markedly elevated gonadotropins seen here; it often causes galactorrhea and is screened for with a serum prolactin level in the amenorrhea workup.
Question 2ReproductiveMedium
A 29-year-old woman has secondary amenorrhea. Pregnancy test is negative. TSH is normal and prolactin is elevated. Which of the following symptoms is most likely associated?
APurple abdominal striae
BAcanthosis nigricans
CBilateral galactorrhea
DRecurrent hot flashes
ECoarse facial hirsutism
Reveal answer & full explanation
Correct answer: C — Bilateral galactorrhea
APurple abdominal striae
BAcanthosis nigricans
CBilateral galactorrhea✓
DRecurrent hot flashes
ECoarse facial hirsutism
Why Bilateral galactorrhea is correct
Elevated prolactin suppresses GnRH, lowering LH and FSH, which explains the secondary amenorrhea.
Prolactin directly stimulates breast milk production, so galactorrhea is the classic accompanying sign of hyperprolactinemia.
A normal TSH excludes hypothyroidism as the driver, isolating prolactin excess as the cause.
Why the others are wrong
Recurrent hot flashes — point to estrogen deficiency from primary ovarian insufficiency or menopause, not prolactin excess (amenorrhea-cause trap).
Coarse facial hirsutism — reflects androgen excess such as PCOS; prolactin elevation does not virilize.
Acanthosis nigricans — is a cutaneous marker of insulin resistance seen with PCOS-related anovulation; prolactin excess does not produce it.
Purple abdominal striae — Cushing syndrome is another endocrine cause of secondary amenorrhea, but there cortisol excess suppresses gonadotropin secretion without raising prolactin, so striae point away from the hyperprolactinemia found here.
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Thyroid disease — Hypo- or hyperthyroid symptoms; abnormal TSH
Primary ovarian insufficiency — Hot flashes, vaginal dryness <40 yo; FSH >25 IU/L (a single elevated value suffices)
Asherman syndrome — Amenorrhea or hypomenorrhea after D&C, endometritis, or uterine surgery; absent withdrawal bleed; hysteroscopy diagnostic
Cushing syndrome / hyperandrogenism (CAH, tumor) — Virilization, central obesity, striae; specific endocrine testing
Diagnostic workup
Diagnostic criteria
Progesterone challenge test (medroxyprogesterone 10 mg × 10 days) can assess estrogen status: bleeding suggests adequate estrogen + patent outflow (anovulation pattern); no bleeding suggests low estrogen OR outflow obstruction OR endometrial unresponsiveness — confirm with estrogen-progestin challenge.
Labs
Pregnancy test (urine or serum hCG) — always first
TSH and prolactin
FSH (high → POI; low/normal → central or PCOS)
If hyperandrogenism: total testosterone, DHEAS, 17-OHP
Estradiol if FSH abnormal
Imaging
Pelvic ultrasound if structural cause suspected
Brain MRI (pituitary protocol) for elevated prolactin or hypogonadotropic hypogonadism
Hysteroscopy or saline sonohysterography if Asherman suspected (history of D&C, endometritis)
Diagnostic algorithm
flowchart TD
A[Secondary amenorrhea] --> B[hCG]
B -->|Positive| C[Pregnancy]
B -->|Negative| D[TSH, prolactin]
D -->|High prolactin| E[Pituitary MRI<br/>Dopamine agonist]
D -->|Abnormal TSH| F[Thyroid treatment]
D -->|Normal| G[FSH, estradiol]
G -->|High FSH| H["Primary ovarian insufficiency<br/>FSH >25 IU/L; repeat in 4-6 wk<br/>only if uncertain"]
G -->|Low/normal FSH| I{Hyperandrogenism?}
I -->|Yes| J[PCOS workup]
I -->|No| K[Progesterone challenge]
K -->|Withdrawal bleed| L["Adequate estrogen with anovulation<br/>(e.g., PCOS)"]
K -->|No bleed| M["E+P challenge"]
M -->|Bleed| N["Hypoestrogenism, patent outflow:<br/>functional hypothalamic amenorrhea,<br/>hypothalamic-pituitary cause"]
M -->|No bleed| O["Outflow or endometrial cause:<br/>Asherman syndrome"]
Algorithm for secondary amenorrhea — pregnancy first, then TSH/prolactin/FSH stratify.
Treatment
First-line
Treat the underlying cause
Pregnancy: prenatal care
PCOS: see PCOS entry — COCP or cyclic progestin
Functional hypothalamic amenorrhea: nutritional restoration, reduce exercise, address stress; CBT for those with eating disorder
Thyroid disease: levothyroxine or antithyroid therapy
POI: hormone therapy (estrogen + progestin) until average age of menopause
Asherman syndrome
Hysteroscopic lysis of adhesions
Postoperative estrogen to promote endometrial regrowth
Intrauterine device or balloon to prevent re-adhesion
Premature ovarian insufficiency
Hormone replacement until ~age 51 (mean menopause age)
Calcium and vitamin D
Fertility counseling — pregnancy possible with donor oocytes
Screen for autoimmune comorbidities (adrenal, thyroid)
Complications
Infertility
Osteoporosis from prolonged hypoestrogenism
Endometrial hyperplasia from unopposed estrogen (PCOS, obesity)
Cardiovascular risk in untreated POI
Psychological distress
PANCE pearls
Always rule out pregnancy first — even with denied sexual activity, contraception use, or recent menses.
Functional hypothalamic amenorrhea is a diagnosis of exclusion; first restore energy availability before starting hormone therapy.
Hyperprolactinemia from medications (antipsychotics, metoclopramide, opioids) usually causes prolactin <100 ng/mL; tumors cause higher levels.
POI is diagnosed in a woman under 40 with at least 4 months of oligo/amenorrhea and a single FSH >25 IU/L; repeat FSH in 4-6 weeks only if the diagnosis is uncertain (2024 ESHRE/ASRM POI guideline).
A withdrawal bleed after progesterone challenge implies adequate endogenous estrogen — proceed with workup for anovulation, not POI.
References
ACOG CO 605 — ACOG Committee Opinion 605: Primary Ovarian Insufficiency in Adolescents and Young Women
Endocrine Society 2017 — Functional Hypothalamic Amenorrhea: Endocrine Society Clinical Practice Guideline (Gordon et al., JCEM 2017)
Endocrine Society 2011 — Diagnosis and Treatment of Hyperprolactinemia: Endocrine Society Clinical Practice Guideline (Melmed et al., JCEM 2011)
ESHRE/ASRM/CRE-WHiRL/IMS 2024 — Panay N, Anderson RA, et al. Evidence-based guideline: premature ovarian insufficiency. Hum Reprod Open 2024;2024(4):hoae065; co-published Fertil Steril 2025;123(2):221-236
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