Menstrual Cycle: Physiology and Disorders
Disclaimer: This article is for informational purposes only and should not be considered as a substitute for professional medical advice.
I. Menstrual Cycle Physiology:
The menstrual cycle is a monthly process in women of reproductive age that involves the shedding of the uterine lining, resulting in menstrual bleeding. A normal menstrual cycle usually lasts from 21 to 35 days, with an average blood flow of 20 to 80 ml.
1. Stages of the Menstrual Cycle:
- Menstrual Phase: (Days 1 – 5): The uterine lining sheds, causing menstrual bleeding.
- Follicular Phase: (Days 6 – 14): An ovarian follicle develops, producing estrogen, and the uterine lining thickens.
- Luteal Phase: (Days 15 – 28): The follicle ruptures, releasing the egg (ovulation). The ruptured follicle forms the corpus luteum, which produces progesterone. The uterine lining prepares for the implantation of a fertilized egg.
2. The Role of Hormones in the Menstrual Cycle:
- GnRH (Gonadotropin-Releasing Hormone): Produced by the hypothalamus, it stimulates the pituitary gland to release FSH and LH.
- FSH (Follicle-Stimulating Hormone): Released by the pituitary gland, it stimulates the development of the ovarian follicle.
- LH (Luteinizing Hormone): Released by the pituitary gland, it triggers ovulation and the formation of the corpus luteum.
- Estrogen: Produced by the ovarian follicle, it thickens the uterine lining and promotes female sexual characteristics.
- Progesterone: Produced by the corpus luteum, it maintains the uterine lining and prepares it for implantation.
II. Menstrual Disorders:
Menstrual disorders refer to any abnormal changes in the cycle, amount, or characteristics of menstrual bleeding. Common menstrual disorders include:
1. Amenorrhea:
- Primary Amenorrhea: No onset of menstruation by age 16, even with normal secondary sexual characteristics.
- Secondary Amenorrhea: Cessation of menstruation for 3 months or more in a woman who previously had regular periods.
2. Dysmenorrhea:
- Primary Dysmenorrhea: Painful periods without any identifiable underlying cause. It is often seen in younger women and may be associated with a narrow cervical opening, a tilted uterus (anteverted or retroverted), or other anatomical factors.
- Secondary Dysmenorrhea: Painful periods due to underlying medical conditions such as endometriosis, fibroids, or infections.
3. Abnormal Menstrual Flow:
- Menorrhagia (Heavy Menstrual Bleeding): Excessive menstrual bleeding, lasting more than 7 days.
- Hypomenorrhea (Light Menstrual Bleeding): Scanty menstrual flow.
- Polymenorrhea (Frequent Menstrual Cycles): Short menstrual cycles, less than 21 days.
- Oligomenorrhea (Infrequent Menstrual Cycles): Long menstrual cycles, more than 35 days.
4. Menstrual Cycle Irregularities:
- Anovulatory Cycles: Menstrual cycles occur without ovulation.
- Precocious Puberty: Menarche before the age of 8.
- Premature Menopause: Cessation of menstruation before the age of 40.
III. Quiz:
1. Question: At what age is the absence of menstruation, despite the presence of normal secondary sexual characteristics, considered primary amenorrhea?
Answer: C. After 18 years of age
2. Question: Which of the following women is LEAST likely to experience primary dysmenorrhea?
Answer: D. Those with a history of a patent cervical os (opening)
3. Question: What is a possible consequence of uterine adhesions (synechiae)?
Answer: C. Amenorrhea
4. Question: Which of the following is NOT a common cause of amenorrhea due to ovarian dysfunction?
Answer: C. Bilateral oophorectomy (surgical removal of both ovaries)
5. Question: Which two hormones are involved in ovulation and a normal menstrual cycle?
Answer: C. FSH and LH
6. Question: What is the duration of amenorrhea that defines secondary amenorrhea?
Answer: A. 3 months or longer
7. Question: Which of the following is NOT a symptom of premenstrual syndrome (PMS)?
Answer: D. Shortness of breath, dizziness
8. Question: Menarche (onset of menstruation) before what age is considered precocious puberty?
Answer: A. < 8 years old
9. Question: What is the age of premature menopause?
Answer: B. Before 40 years old
10. Question: What is the length of a menstrual cycle considered oligomenorrhea?
Answer: B. > 35 days
11. Question: What is the length of a menstrual cycle considered polymenorrhea?
Answer: B. < 21 days
12. Question: How many days of menstrual bleeding define menorrhagia?
Answer: C. > 7 days
13. Question: Which of the following is NOT a condition associated with physiological amenorrhea?
Answer: D. Imperforate hymen (unruptured hymen)
14. Question: Which of the following is NOT a principle of managing menorrhagia or metrorrhagia (irregular bleeding)?
Answer: C. Hormonal therapy for young, nulliparous women (women who have never given birth)
15. Question: Which of the following is NOT a cause of secondary dysmenorrhea?
Answer: D. Increased pain sensitivity and emotional reactivity
16. Question: Which of the following is NOT a preventive measure for secondary dysmenorrhea?
Answer: D. Intrauterine device (IUD) insertion to prevent uterine adhesions
17. Question: How do FSH and LH levels change in menopausal women?
Answer: A. FSH and LH increase
18. Question: In a postmenopausal woman, what endometrial thickness on ultrasound suggests endometrial hyperplasia (thickening)?
Answer: D. > 04 mm
19. Question: Which of the following is NOT a possible cause of heavy, prolonged menstrual bleeding?
Answer: B. Oral contraceptive use
20. Question: Which of the following is NOT a physical cause of menstrual disorders?
Answer: C. Hormonal imbalance
21. Question: What is the main cause of anovulatory cycles?
Answer: D. Lack of progesterone production with fluctuating estrogen levels.
22. Question: Why do women with anovulatory cycles often seek medical attention?
Answer: A. Difficulty conceiving.
23. Question: Which of the following is a universal approach for treating anovulatory cycles to induce ovulation?
Answer: D. Treatment varies depending on the specific cause.
24. Question: What is functional menorrhagia or metrorrhagia?
Answer: C. It is often seen during puberty or perimenopause.
25. Question: Which of the following statements is incorrect about functional menorrhagia or metrorrhagia?
Answer: B. Bleeding is excessive and difficult to manage, often requiring hysterectomy.
26. Question: Which of the following should NOT be done to diagnose functional menorrhagia or metrorrhagia?
Answer: D. Laparoscopy (a surgical procedure to view the abdominal cavity)
27. Question: What is the average age of menopause?
Answer: D. Between 45 and 55 years old
28. Question: Dysmenorrhea often…
Answer: C. Can cause pain before, during, and after menstruation.
29. Question: From what point is the menstrual cycle calculated?
Answer: C. From the first day of the current cycle to the first day of the next cycle.
30. Question: What gland produces FSH and LH?
Answer: B. Pituitary gland
31. Question: Which of the following is a true statement about amenorrhea?
Answer: C. One possible cause is adrenal hyperplasia (overgrowth of the adrenal glands).
32. Question: What is the approach to treating polymenorrhea (frequent cycles)?
Answer: A. Use estrogen at the beginning of the cycle and add progesterone before menstruation.
33. Question: Menstruation occurs because of… (a decline in estrogen and progesterone) …leading to… (shedding of the uterine lining)…which results in…(bleeding) …from the uterus.
Answer: (a decline in estrogen and progesterone), (shedding of the uterine lining), (bleeding)
34. Question: Name four syndromes that cause primary amenorrhea.
Answer:
- A. Turner Syndrome
- B. Adrenogenital Syndrome
- C. Mayer-Rokitansky-Kuster-Hauser Syndrome
- D. Androgen Insensitivity Syndrome
35. Question: What is the primary cause of the monthly menstrual bleeding in women of reproductive age?
Answer: B. Decline in estrogen and progesterone
36. Question: A woman’s blood tests show low estrogen, low progesterone, high FSH, and high LH. Which of the following is the most likely diagnosis?
Answer: B. Ovarian insufficiency
37. Question: What is the first step when a 25-year-old woman presents with amenorrhea for 3 months?
Answer: C. Rule out pregnancy.
38. Question: Which of the following causes of amenorrhea has the highest success rate with treatment?
Answer: D. Imperforate hymen
39. Question: Hypomenorrhea (light menstrual bleeding) can occur due to:
Answer: C. Prolonged use of progestin-only contraceptives
40. Question: What is the main reason why women with anovulatory cycles often seek medical attention?
Answer: A. Difficulty conceiving
41. Question: What is functional menorrhagia or metrorrhagia?
Answer: C. It is often seen during puberty or perimenopause.
42. Question: Which of the following are potential causes of delayed puberty (puberty)?
Answer: D. Both B and C are correct.
43. Question: Menstruation is caused by:
Answer: D. A sudden decline in estrogen and progesterone
44. Question: How is menorrhagia often treated in young girls going through puberty?
Answer: A. Progesterone.
45. Question: Which of the following is a universal approach for treating anovulatory cycles to induce ovulation?
Answer: D. Treatment varies depending on the specific cause.
46. Case Study 1:
- (1). A 15-year-old girl presents to the clinic for lower abdominal pain. What are 3 questions you should ask?
- (1). A. (Describe the pain)
- (1). B. (Past medical history)
- (1). C. (Menstrual history)
- (2). After questioning, you learn that she has had monthly pain recently and has not yet started her periods. What is the preliminary diagnosis?
- (2). Menstrual cramps (dysmenorrhea)
- (3). If this is the diagnosis, what should you focus on during the physical examination?
- (3). Look for any genital abnormalities
47. Case Study 2:
- (1). A woman who underwent an abortion 2 months ago comes for evaluation because her period has not returned. What are 3 possible diagnoses?
- (1). A. Pregnancy.
- (1). B. Delayed return of menstruation.
- (1). C. (Uterine adhesions)
- (2). What tests and investigations should be performed to rule out these diagnoses?
- (2). A. (Hormone levels)
- (2). B. (hCG test)
- (2). C. (Uterine sound)
- (2). D. (Hysterosalpingography (HSG) – imaging of the uterus and fallopian tubes)
Note: Answers in the quiz section are highlighted for easy identification.
This article provides information about the menstrual cycle and its disorders. If you have any concerns about your health, please consult your doctor for advice and prompt treatment.
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