No menarche by age 15 with secondary sex characteristics, or by 13 without them.
Also known as: primary amenorrhea, delayed puberty, no menarche
Overview
Absence of menses by age 15 in a girl with normal secondary sexual development, or by age 13 in a girl with absent secondary sexual development. Evaluation may begin earlier with absent breast development by 13 or no menarche 3 years after thelarche.
Epidemiology
Affects ~0.1-2.5% of adolescents. Most common causes: gonadal dysgenesis (Turner 45,X), Müllerian agenesis (MRKH), constitutional delay, and functional hypothalamic amenorrhea.
Try two board-style Primary Amenorrhea questions
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Question 1ReproductiveMedium
A 19-year-old female has never had a menstrual period. She has sparse pubic hair and axillary hair, and minimal breast development (Tanner 2). She is 5 feet 2 inches. Pelvic ultrasound shows small streak gonads. Karyotype is 45,X. FSH is markedly elevated at 98 IU/L. LH is 65 IU/L. Estrogen is very low. Which of the following is the most likely diagnosis?
A46,XX gonadal dysgenesis
BPremature ovarian insufficiency
CKallmann syndrome
DTurner syndrome
Reveal answer & full explanation
Correct answer: D — Turner syndrome
A46,XX gonadal dysgenesis
BPremature ovarian insufficiency
CKallmann syndrome
DTurner syndrome✓
Why Turner syndrome is correct
Turner syndrome (45,X or mosaicism): most common sex chromosome abnormality in females (1 in 2,500)
Karyotype 45,X with streak gonads (fibrous tissue, no oocytes) confirms gonadal dysgenesis → primary ovarian failure → primary amenorrhea and infertility
Markedly elevated FSH (98 IU/L) and LH (65 IU/L) with very low estrogen = hypergonadotropic hypogonadism
Short stature is characteristic (average untreated adult height 143–147 cm); heights near 5'2" occur with mosaicism or prior growth hormone therapy
Why the others are wrong
46,XX gonadal dysgenesis — also produces streak gonads, primary amenorrhea, and hypergonadotropic hypogonadism, but by definition the karyotype is 46,XX, which the 45,X reported here excludes
Premature ovarian insufficiency — occurs in chromosomally normal females (46,XX) under age 40; would not explain 45,X karyotype or streak gonads
Kallmann syndrome — hypogonadotropic hypogonadism with anosmia; FSH and LH would be low rather than the 98 IU/L and 65 IU/L reported here
Treatment: growth hormone (GH) starting in childhood (increases adult height by 7–8 cm); estrogen at 11–12 years for puberty induction; combined estrogen-progestin after puberty induction to prevent osteoporosis and CV disease; fertility via in vitro fertilization (IVF) with donor oocytes
Question 2ReproductiveMedium
A 16-year-old girl presents for evaluation of never having had a menstrual period. She reports normal breast development beginning at age 11 and denies pelvic pain. On exam, breast and pubic hair are Tanner stage 5, and external genitalia are normal female with a shortened, blind-ending vaginal pouch. Pelvic ultrasound shows an absent uterus and upper vagina with two normal ovaries. Karyotype is 46,XX and serum total testosterone is in the normal female range. Which of the following is the most appropriate initial management?
AGraduated vaginal dilator therapy
BTransvaginal hymenotomy procedure
CCyclic estrogen-progestin therapy
DBilateral laparoscopic gonadectomy
Reveal answer & full explanation
Correct answer: A — Graduated vaginal dilator therapy
AGraduated vaginal dilator therapy✓
BTransvaginal hymenotomy procedure
CCyclic estrogen-progestin therapy
DBilateral laparoscopic gonadectomy
Why Graduated vaginal dilator therapy is correct
The picture is Müllerian agenesis (MRKH): normal breast and pubic hair development with a 46,XX karyotype, normal female-range testosterone, two normal ovaries, and an absent uterus and upper vagina ending in a blind pouch.
Because the ovaries are functional, endogenous estrogen is intact and hormone replacement is unnecessary; the unmet need is creation of a functional vagina.
ACOG endorses graduated vaginal dilation as first-line management for MRKH, reserving surgical neovagina creation for patients who fail or decline dilation.
Why the others are wrong
Cyclic estrogen-progestin therapy is first-line for hypoestrogenic causes such as Turner syndrome or primary ovarian insufficiency, but this patient has normal ovaries and normal estrogen, so it is not needed.
Bilateral laparoscopic gonadectomy is indicated when Y-chromosome material is present (e.g., complete androgen insensitivity, 46,XY) to prevent gonadoblastoma; here the karyotype is 46,XX with two normal ovaries, so this would remove healthy tissue.
Transvaginal hymenotomy corrects outflow obstruction from an imperforate hymen, which presents with cyclic pelvic pain and a bulging hymen with hematocolpos; this patient has no pain and a true absence of the uterus and upper vagina, not an obstructed outflow tract.
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Family history of delayed puberty or genetic disorders
Chronic illness, malnutrition, low body weight
Excessive exercise, eating disorders
Stress, depression
Pelvic radiation or chemotherapy
Pathophysiology
Menarche requires an intact hypothalamic-pituitary-ovarian axis, functional outflow tract, and adequate body composition. Disruption at any level — central (hypothalamus/pituitary), gonadal (ovary), or anatomic (uterus/vagina/hymen) — can prevent menses. Genetic causes (Turner syndrome, complete androgen insensitivity) are disproportionately common in primary amenorrhea.
Clinical presentation
Symptoms
Absence of menses by expected age
Cyclic pelvic pain (outflow obstruction)
Short stature, primary cardiac or renal anomalies (Turner)
Brain MRI (pituitary protocol) — if low gonadotropins or hyperprolactinemia
Bone age (left hand and wrist) for constitutional delay assessment
Diagnostic algorithm
flowchart TD
A[Primary amenorrhea<br/>± delayed puberty] --> B[hCG, FSH, LH,<br/>estradiol, TSH, prolactin]
B --> C[Pelvic ultrasound:<br/>uterus present?]
C -->|No uterus| D[Karyotype + testosterone]
D --> E[46,XX → Müllerian agenesis]
D --> F[46,XY + high T<br/>→ Androgen insensitivity]
C -->|Uterus present| G{FSH level}
G -->|High| H[Hypergonadotropic<br/>→ karyotype<br/>Turner / POI]
G -->|Low/normal| I[Hypogonadotropic<br/>→ brain MRI<br/>Kallmann, prolactinoma,<br/>functional HA]
G -->|Normal + outflow Sx| J[Outflow obstruction:<br/>imperforate hymen,<br/>transverse septum]
Workup algorithm for primary amenorrhea — uterus presence and FSH guide diagnosis.
Treatment
First-line
Treat the underlying cause
Reassurance and observation for constitutional delay
Hormone replacement (low-dose estrogen → eventual COCP) for primary ovarian insufficiency including Turner syndrome
Multidisciplinary care for genetic syndromes; psychological support and counseling about fertility/sexuality
Vaginal dilator therapy or surgical neovagina for Müllerian agenesis
Hypergonadotropic hypogonadism (high FSH)
Karyotype
Turner syndrome: estrogen replacement starting low-dose at 11-12 yo, progressively increase, add progestin once breakthrough bleeding occurs or after 2 years
Gonadectomy for any Y-chromosome material (risk of gonadoblastoma)
Fertility counseling: donor oocyte IVF
Hypogonadotropic hypogonadism (low FSH)
Brain MRI for structural cause
Treat underlying cause (low weight, excessive exercise, prolactinoma)
Pulsatile GnRH or gonadotropins for fertility
Estrogen-progestin replacement for bone health
Outflow obstruction
Imperforate hymen: hymenotomy
Transverse septum: surgical resection
Müllerian agenesis: vaginal dilation (first-line) or neovaginal surgery
Complications
Osteoporosis from prolonged estrogen deficiency
Cardiovascular risk in untreated hypogonadism (esp. Turner)
Infertility and need for assisted reproduction
Psychological impact of delayed development and fertility issues
Gonadoblastoma risk in dysgenetic gonads with Y material — prophylactic gonadectomy indicated
PANCE pearls
Always check a pregnancy test first, regardless of stated sexual history.
Absent uterus + breast development → either Müllerian agenesis (46,XX, normal testosterone) or complete androgen insensitivity (46,XY, male-range testosterone).
Cyclic pelvic pain in a patient with no menses suggests outflow obstruction (imperforate hymen, transverse septum).
Any Y-chromosome material in a phenotypic female requires gonadectomy due to gonadoblastoma risk.
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