Snapshot A 17-year-old female presents to the pediatrician with a concern of not yet beginning menses. Her friends in high school have already begun menses a few years ago, and this brings the patient great distress. She reports being sexually active and uses condomns consistently. She does not use any other form of contraception. She denies pelvic pain. On physical exam, there is normal breast development; however, her uterus is not palpable. This is confirmed by pelvic ultrasound. Karyotype returns as 46, XX and serum testosterone level is appropriate for a female. (Müllerian agenesis) Introduction Absence of menarche by the age of ≥ 15 years with normal secondary sexual characteristics and normal growth or ≥ 13 years with the absence of secondary sexual characteristics Etiology most cases are due to genetic causes or anatomical abnormalities examples include gonadal dysgenesis e.g., Turner syndrome Müllerian agenesis e.g., absent uterus and vagina physiological delay of puberty polycystic ovarian syndrome hypopituitarism androgen insensitivity syndrome complete androgen insensitivity syndrome with 46 XY karyotype, male gonads and external female characterics (breasts, vulva, short vagina, absent cervix/uterus), and no/minimal axillary or pubic hair general principle etiologies can be divided by issues involving the hypothalamus pituitary ovaries uterus vagina Presentation Symptoms absence of menses There are many causes of primary amenorrhea, and depending on the cause, it may affect clinical presentation e.g., patient with Müllerian agenesis may have an absent uterus on physical exam transverse vaginal septa present with normal pubertal development and normal uterus/ovaries Imaging Pelvic ultrasound is needed to determine the presence of a uterus STUDIES In a patient with primary amenorrhea and an increased FSH, the next step in management is karyotyping Differential Pregnancy Contraceptive use Refer to evaluation Treatment Directed at underlying pathology e.g., vaginal outlet obstruction will require surgical correction COMPLICATIONS Infertility