# Primary Amenorrhoea Evaluation > Primary amenorrhoea evaluation for NEET-PG Obstetrics and Gynaecology, stepwise separation of Turner, Müllerian agenesis and androgen insensitivity. - Canonical URL: https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/primary-amenorrhoea-evaluation - Exam / course: NEET-PG · Subject: Obstetrics and Gynaecology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-08 - Last updated: 2026-10-08 - Reference basis: Williams Obstetrics; Speroff's Clinical Gynecologic Endocrinology and Infertility; Shaw's Textbook of Gynaecology - How to cite: "Primary Amenorrhoea Evaluation", PrepElephant, https://prepelephant.com/topics/neet-pg/obstetrics-and-gynaecology/primary-amenorrhoea-evaluation ## Direct answer Primary amenorrhoea is the absence of menarche by age 15 years with normal secondary sexual characteristics, or by 13 years when none have appeared. Its evaluation separates causes stepwise by breast development, uterine presence and FSH level. Absent breasts with raised FSH point to Turner syndrome or gonadal dysgenesis, while normal breasts with an absent uterus point to Müllerian agenesis or androgen insensitivity, which are separated by karyotype. ## What you must remember - **Definition:** no menarche by 15 years with normal secondary features, by 13 years without any, or more than three years after breast development began. - **First branch:** absent breast development points to gonadal failure or hypogonadotrophism, while present breasts point to a uterine or outflow problem. - **Turner syndrome:** 45,X karyotype with raised FSH and streak gonads, often with short stature, webbed neck and a broad chest. - **Müllerian agenesis:** 46,XX karyotype with normal breasts, pubic hair and ovaries, but an absent uterus and upper vagina. - **Androgen insensitivity:** 46,XY karyotype with female external genitalia, normal breasts from peripheral conversion of testicular androgen, no uterus, and gonads removed after puberty. - **Imperforate hymen:** normal breasts and pubic hair with cyclical pain, a bluish bulge at the introitus, and a fluid-filled uterus or vagina on ultrasound. - **Hormonal pattern:** raised FSH indicates ovarian failure; low FSH with low oestradiol points to a hypothalamic or pituitary cause, and prolactin and TSH must be checked. - **Karyotype rule:** obtain karyotype whenever breasts are absent or the uterus is missing, because Y-chromosome material carries a gonadal tumour risk. ## A stepwise approach from breasts to karyotype The evaluation works as a decision tree, so each test is ordered only after the previous branch has been answered. Examination comes first, then the uterus and FSH decide the next step. 1. **Confirm the diagnosis:** check age, breast staging and pregnancy status, since pregnancy is excluded before any other test. 2. **Stage secondary characteristics:** absent breast development points to gonadal failure or hypogonadotrophism, while present breasts point to an outflow or uterine cause. 3. **Assess the uterus:** pelvic ultrasound or MRI shows whether a uterus is present, and an absent uterus with normal breasts narrows the list to Müllerian agenesis or androgen insensitivity. 4. **Measure FSH, LH and oestradiol:** raised FSH with small or streak ovaries suggests Turner syndrome or gonadal dysgenesis, while low FSH suggests a hypothalamic or pituitary cause. 5. **Send karyotype:** 45,X confirms Turner syndrome; 46,XX with an absent uterus indicates Müllerian agenesis, and 46,XY with male-range testosterone indicates androgen insensitivity. 6. **Look for outflow obstruction:** a present uterus with normal breasts and cyclical pain needs examination for an imperforate hymen or transverse vaginal septum, with imaging of the vagina and uterus. ## Where the decision tree goes wrong Most lost marks come from accepting a plausible diagnosis before the discriminating test has been done. - **Trap:** Labelling an absent uterus with normal breasts as Turner syndrome — **Correct:** Turner is 45,X with raised FSH and small or streak ovaries; normal breasts with an absent uterus point to Müllerian agenesis or androgen insensitivity, which need karyotype. - **Trap:** Assuming a present uterus rules out outflow problems — **Correct:** A present uterus with normal breasts and cyclical pain suggests an imperforate hymen or transverse septum, which ultrasound can show. - **Trap:** Ordering a pituitary MRI for every low FSH — **Correct:** Imaging is directed by markedly raised prolactin, headache or visual field loss, not by a low FSH alone. - **Trap:** Skipping karyotype when the uterus is absent — **Correct:** Karyotype separates Müllerian agenesis from androgen insensitivity; without it, the risk from retained testes goes unrecognised. ## Frequently asked questions ### Which karyotype separates Müllerian agenesis from androgen insensitivity? Müllerian agenesis is 46,XX with normal ovaries, while androgen insensitivity is 46,XY with testes and male-range testosterone levels. Both have an absent uterus and normal breast development, so the karyotype is the discriminating test. ### Why is FSH measured in primary amenorrhoea? FSH distinguishes ovarian failure, with raised FSH as in Turner syndrome or gonadal dysgenesis, from hypothalamic or pituitary causes, which give low or normal FSH. It is the main hormonal test that splits the causes at the first branch of the evaluation. ### When should an imperforate hymen be suspected in primary amenorrhoea? Imperforate hymen is suspected in a girl with normal breasts and pubic hair who has cyclical lower abdominal pain, no menses, and a bluish bulge at the introitus. Ultrasound showing a fluid-filled uterus or vagina supports the diagnosis. ### Is karyotype needed in every girl with features of Turner syndrome? Karyotype is needed to confirm Turner syndrome, because it detects mosaicism and Y-chromosome material, which carries a gonadal tumour risk that may call for gonadectomy. Clinical features alone are not enough to make the diagnosis.