Which of the following is the most common cause of primary amenorrhea in India?

Explanation

## Primary Amenorrhea: Most Common Cause in India **Key Point:** Gonadal dysgenesis (most commonly Turner syndrome, 45,XO) is the most common *pathological* cause of primary amenorrhea, accounting for approximately 30–40% of cases in most Indian and global series. It is consistently cited as the single most common cause in standard Indian gynecology textbooks (Dutta's Textbook of Gynecology, Shaw's Textbook of Gynecology). ### Why Gonadal Dysgenesis? **High-Yield:** Gonadal dysgenesis presents with: - Primary amenorrhea (no menarche by age 15) - Absent or rudimentary secondary sexual characteristics (streak gonads → low estrogen) - Short stature, webbed neck, shield chest, wide-carrying angle (Turner syndrome features) - Elevated FSH and LH (hypergonadotropic hypogonadism) - Karyotype: 45,XO (classic Turner) or mosaic variants (45,XO/46,XX) ### Differential Diagnosis of Primary Amenorrhea | Cause | Prevalence (%) | Key Features | |-------|---|---| | Gonadal dysgenesis (Turner syndrome) | 30–40 | Short stature, webbed neck, hypergonadotropic hypogonadism | | Müllerian agenesis (MRKH) | 10–15 | Normal secondary sexual characteristics, absent uterus/vagina | | Physiological delay of puberty | 10–20 | Diagnosis of exclusion; normal growth velocity, delayed bone age | | Androgen insensitivity syndrome | 5–10 | Phenotypic female, absent uterus, 46,XY karyotype | | Hypothyroidism/Hyperprolactinemia | 5–10 | Systemic symptoms, elevated TSH or prolactin | **Clinical Pearl:** Physiological delay of puberty (constitutional delay) is more commonly cited as the most frequent cause of *delayed puberty in boys*. In girls presenting with primary amenorrhea to a gynecology clinic, gonadal dysgenesis is the leading diagnosis per Dutta's Gynecology (7th ed.) and Shaw's Gynecology (16th ed.). **Why not Physiological Delay of Puberty?** Constitutional delay is predominantly a male diagnosis and is a diagnosis of exclusion. In clinical series of primary amenorrhea in Indian women, gonadal dysgenesis consistently ranks first as the identifiable cause. **Mnemonic:** **G**onadal dysgenesis **G**oes first — the most common cause of primary amenorrhea in girls presenting to clinic. [cite: Dutta's Textbook of Gynecology 7e; Shaw's Textbook of Gynecology 16e; Williams Gynecology 4e]