Diagnostic Approach to Primary Amenorrhea with Normal Breast Development

Initial Evaluation

A 19-year-old with normal breast development and primary amenorrhea should undergo initial evaluation including pelvic ultrasound to assess uterine anatomy, pregnancy testing, and hormonal assessment, as outflow tract obstruction or Müllerian agenesis are likely causes 1, 2
Pregnancy test must be performed first to exclude pregnancy, as recommended by the American College of Obstetricians and Gynecologists 1, 3
Pelvic ultrasound is essential to assess whether a uterus is present and to identify structural abnormalities, according to the Society of Radiologists in Ultrasound 1, 2
Hormonal panel including FSH, LH, prolactin, and TSH should be obtained to evaluate hormonal imbalances, as suggested by the Endocrine Society 1, 2, 3

Polycystic ovary syndrome (PCOS) should be considered if the ultrasound shows normal anatomy but amenorrhea persists, characterized by LH/FSH ratio >2, polycystic ovarian morphology on ultrasound, and signs of hyperandrogenism, as defined by the American College of Obstetricians and Gynecologists 1, 2
Functional hypothalamic amenorrhea should be assessed for eating disorders, excessive exercise, low BMI, and psychosocial stressors, as recommended by the American Psychological Association 3, 2
Hyperprolactinemia should be evaluated if prolactin is elevated (>20 μg/L), which may indicate pituitary adenoma, according to the Endocrine Society 1, 3
Primary ovarian insufficiency should be considered if FSH is elevated (>40 mIU/mL) confirmed on repeat testing 4 weeks later, as defined by the American Society for Reproductive Medicine 1, 3

Evaluate for bone density loss if amenorrhea has been prolonged (>6 months), particularly in functional hypothalamic amenorrhea, as recommended by the National Osteoporosis Foundation 3, 2
Screen for eating disorders in thin or athletic patients, as these are commonly underreported, according to the American Psychological Association 1, 2
Gynecology and/or endocrinology consultation is strongly recommended for primary amenorrhea by age 16 years with normal pubertal development, suspected outflow tract obstruction, absent uterus, or elevated FSH, as suggested by the American College of Obstetricians and Gynecologists 4, 3