Women's Health : Oligomenorrhea + amenorrhea Flashcards
What is oligomenorrhea?
Infrequent or irregular menstrual periods, variably defined as fewer than 6–8 periods per year.
Define amenorrhea.
The absence of a menstrual period.
What is primary amenorrhea?
○ Primary amenorrhea: absence of a period at age 15 in the presence of normal secondary sexual characteristics or at age 13 with no secondary sexual characteristics
Define secondary amenorrhea.
Secondary amenorrhea: absence of a period for three consecutive cycles in a woman with a previously established menstrual cycle.
List common causes of primary amenorrhea.
○ Constitutional delay (familial) ○ Imperforate hymen ○ Hypo- / hyperthyroidism, hyperprolactinaemia, Cushing’s syndrome ○ Androgen insensitivity syndrome ○ Turner’s syndrome
List common causes of secondary amenorrhea.
○ Functional Hypothalamic Amenorrhea - excessive exercise, weight loss, stress, eating disorders. ○ Premature ovarian insufficiency ○ Sheehan’s syndrome, prolactinoma, hypopituitarism ○ Hypo- / hyperthyroidism
What is PCOS?
An endocrinopathy characterized by ovarian cysts, oligomenorrhea, and hyperandrogenism.
What are the Rotterdam criteria for diagnosing PCOS?
a woman must meet 2 of the 3: 1. Hyperandrogenism 2. Oligo- or anovulation 3. Polycystic morphology on ultrasound
True or False: PCOS requires ovarian cysts for diagnosis.
False. PCOS can be diagnosed in the absence of ovarian cysts if other criteria are met.
Explain the disrupted hormonal balance in PCOS.
Disrupted balance between androgens, anti-Mullerian hormone and FSH levels leads to arrest in follicular development: a. Increased GnRH release frequency leads to high LH:FSH ratio. b. This results in high androgen:oestradiol ratio. c. Low oestrogen (due to reduced granulosa cell activity) prevents follicle selection and subsequent ovulation. Instead, multiple immature follicles remain and form cysts. d. Additionally, high androgens may inhibit sex steroid negative feedback on the HPG axis, leading to a ‘vicious circle’ of rising androgens
How does insulin resistance contribute to PCOS?
Insulin resistance and hyperinsulinaemia: a. Peripheral insulin resistance (skeletal muscle, adipose tissue) leads to hyperglycaemia and subsequent hyperinsulinaemia. b. High insulin levels stimulate theca cell androgen production and reduce sex-hormone binding globulin levels (SHBG); this means increased free circulating androgens.
List common symptoms of PCOS.
Hyperandrogenism: hirsutism, acne, hyperhidrosis. ● Oligomenorrhea - due to oligo-ovulation. ● Subfertility / infertility
Name risk factors for PCOS.
- Obesity 2. Family history 3. Premature adrenarche (pubic / axillary hair, apocrine sweat gland development).
Which investigations help diagnose PCOS?
- Total serum testosterone - elevated 2. Sex hormone-binding globulin (SHBG) - normal to low 3. Free androgen index - elevated 4. Rule-out tests: LH and FSH , prolactin, TFTs . 5. Imaging:
Which tests rule out PCOS?
LH and FSH (premature ovarian failure), prolactin (hyperprolactinaemia), TFTs (hypothyroidism); used to eliminate other causes of oligomenorrhea
What imaging finding leads to dx of PCOS?
12 or more follicles on one ovary
What is the first-line treatment for PCOS if fertility is not desired?
COCP for cycle regulation plus weight loss. For prolonged amenorrhea: cyclic progesterone every 3 months to protect the endometrium.
What is the second-line treatment for PCOS if fertility is not desired?
(in event of prolonged amenorrhea) a. Cyclical progesterone (taken for 14 days every 3 months) to induce a withdrawal bleed to protect endometrium. b. Also offer transvaginal USS to assess endometrial thicknes
What is the first-line treatment for PCOS if fertility is desired?
weight loss plus: a. Clomifene or b. Letrozole (aromatase inhibitor).
What are second-line treatments for PCOS-related infertility?
Metformin to improve insulin sensitivity
How does the COCP help in PCOS?
regulation of menstrual cycle through stabilisation of oestrogen & progesterone levels. Also increases hepatic SHBG production (lowering free androgen index) and blocks some androgen receptors
How does Metformin treat PCOS?
- improves peripheral insulin sensitivity to downregulate effects of insulin resistance described above.
What is the mechanism of action of Clomifene?
selective oestrogen receptor modulator; blocks hypothalamic oestrogen receptors, thereby inhibiting HPG axis negative feedback and inducing FSH / LH secretion to lead to ovulation
How does Letrozole work in PCOS?
aromatase inhibitor, inhibits peripheral conversion of androgens into oestrogen, reducing HPG axis negative feedback to promote ovulation.
