Menstrual Cycle — Physiology

A 28-year-old woman presents with amenorrhea for 3 months. Her last menstrual period was 12 weeks ago. Physical examination is unremarkable. Urine pregnancy test is negative. Which investigation is most appropriate to determine the phase of the menstrual cycle and assess ovulatory status?

A 32-year-old woman with a history of regular 28-day cycles presents with 2 months of amenorrhea. She is not sexually active and denies pregnancy symptoms. Urine β-hCG is negative. TSH, prolactin, and FSH are all normal. Pelvic ultrasound shows normal endometrial thickness (8 mm) and normal ovaries. A progestin challenge test (medroxyprogesterone acetate 10 mg daily for 5 days) is performed, and she does not menstruate within 7 days. What is the most appropriate next step?

Which hormone shows a sharp surge 24–36 hours before ovulation in the menstrual cycle?

A 32-year-old woman with a regular 28-day menstrual cycle reports heavy menstrual bleeding (menorrhagia) and dysmenorrhea. She wishes to understand the hormonal basis of her symptoms. Which investigation would best demonstrate the peak of the luteal phase and correlate with her symptoms?

A 28-year-old woman from Delhi presents to the gynaecology clinic with a 6-month history of irregular menstrual cycles. Her cycles vary between 24 and 35 days, with cycle length unpredictability. Menarche was at age 13, and she has no history of hormonal contraceptive use. Physical examination is unremarkable. Serum FSH on day 3 of the cycle is 6.2 mIU/mL (normal range 3.5–12.5 mIU/mL), and serum progesterone on day 21 is 8 ng/mL (normal luteal phase >5 ng/mL). Transvaginal ultrasound shows a normal-sized uterus with 8–10 follicles in each ovary. Which physiological disturbance best explains her cycle irregularity?