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Reproductive system




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A 17-year-old girl comes to the office for the evaluation of amenorrhea. The patient’s menarche was at the age of 13, and her menstrual cycle has been regular with menses occurring every 28 days. For the past 8 months, the patient has not menstruated. She is sexually active with her boyfriend and uses condoms consistently. The patient plays on the high school soccer team and frequently competes in local beauty pageants. She follows a calorie-restricted dietary regimen and exercises 3 hours every day. Temperature is 37°C (98.6°F), pulse is 95/min, respirations are 18/min and blood pressure is 90/55 mmHg. BMI is 16 kg/m2. Physical examination shows a pale, thin girl of normal stature with fine hair and Tanner stage III breast and pubic hair growth. Rest of the examination is within normal limits. Urine pregnancy test is negative. Which of the following set of hormonal changes will be observed in this patient?  

External References

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antiandrogens p. 682

cirrhosis p. 398

Cushing syndrome p. 354

cystic fibrosis p. 58

ectopic pregnancy and p. NaN

menopause p. 652

Müllerian agenesis p. 646

PCOS p. 670

pituitary adenoma and p. 544

pituitary prolactinomas p. 335

Turner syndrome p. 661


Content Reviewers


Amenorrhea means no menstruation.

It’s normal before puberty, during pregnancy and lactation, and after menopause.

Sometimes though, menstruation either never starts, which is called primary amenorrhea, or suddenly stops in a person who’s previously menstruating, which is called secondary amenorrhea.

Now, menstruation, and the menstrual cycle as a whole are controlled by the hypothalamus and the pituitary gland, all the way up in the brain.

The hypothalamus secretes gonadotropin-releasing hormone, or GnRH, which makes the nearby anterior pituitary gland release follicle-stimulating hormone, or FSH, and luteinizing hormone, or LH.

In the first two weeks of a normal 28-day cycle, the ovaries go through the follicular phase, meaning that out of the many follicles scattered throughout the ovaries, a couple of them enter a race to become the dominant follicle, that will be released at ovulation.

All the developing follicles secrete loads of estrogen, which negatively inhibits pituitary FSH.

In the meantime, the uterus goes through two phases: the menstrual and proliferative phase.

During the menstrual phase, the functional layer of the endometrium is shed and eliminated through the vagina, leading to menstruation, which lasts an average of five days.


Amenorrhea is the absence of menstrual periods in women during reproductive years. There are two types of amenorrhea: primary and secondary. Primary amenorrhea is when periods have never started by the time a girl reaches 16 years old. Secondary amenorrhea is when periods have stopped for at least three months, even if they had started in the past.

There are many possible causes of amenorrhea, including pregnancy, hormone problems, problems with the ovaries or uterus, eating disorders, excessive exercise, and stress.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Luteinizing Hormone Pulsatility Is Disrupted at a Threshold of Energy Availability in Regularly Menstruating Women" The Journal of Clinical Endocrinology & Metabolism (2003)
  6. "Evaluation of extended and continuous use oral contraceptives" Therapeutics and Clinical Risk Management (2008)
  7. "Role of leptin in energy-deprivation states: normal human physiology and clinical implications for hypothalamic amenorrhoea and anorexia nervosa" The Lancet (2005)

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