OB Gyn C3 Ch4 - PP: Menstrual Cycle

Hormone levels during the menstrual cycle are controlled by a feedback system between which glands?

Ovaries, hypothalamus, and anterior hypophysis of the pituitary gland

Rise in LH causes

Ovulation to occur

How many follicles are stimulated by FSH to grow each month?

5-7 (up to 11 total)

What age does menstruation start?

10-14 yrs

Cesation of menstruation is aka

Menopause

Menopause occurs at what age?

45-55yrs

First menstruation is aka

Menarche

How long is the average menstrual cycle?

28 days

How many phases are there in a menstrual cycle?

3

What is considered a normal menstrual cycle length?

Between 21-35 days (usually remains fairly consistent from month to month)

Dysmenorrhea is

Painful menstruation

What is menstruation?

A cyclic process whereby the endometrial lining is shed if implantation of a conceptus has not occurred

Hypomenorrhea is

Abnormally small amount of menstrual bleeding

Amenorrhea is

Absence of menstrual flow. May be primary (never menstruated by age 16) or secondary (menstruation has ceased for the equivalent of 3 menstrual cycles or 6 months)

Common causes of secondary amenorrhea include

Anorexia or athletic training (both related to low body fat %)

When does ovulation typically occur in an avg 28 day menstrual cycle?

Approximately day 14

What are the pros of HRT?

Decreases menopausal symptoms (hot flashes, vaginal dryness, etc), prevents loss of bone density, raises good cholesterol (HDL) and lowers bad cholesterol (LDL).

What occurs in the menstrual phase of the menstrual cycle?

Endometrium degenerates, then sloughs away from the myometrium. Sloughed endometrium is then expelled at mensus. Mensus typically has 12-24 hours of heavy flow followed by lighter flow for the next 4-7 days.

Developing follicles in the ovary release

Estrogen (1)

Proliferative phase of menstrual cycle is associated with

Estrogen (2)

How do oral contraceptives influence the menstrual cycle?

Estrogen / progestin combo pills and progestin only pills or implants prevent the pituitary gland from releasing LH that stimulates ovulation.

Ovaries is associated with what hormone?

Estrogen and progesterone

Endometrium responds to

Estrogen and progesterone levels in the blood stream

Menorrhagia is

Excessive menstrual bleeding in duration (7+ days) or volume (greater than 80ml per cycle)

Hypermenorrhea is

Excessive volume of blood during menstruation

What denotes the onset of the secretory phase?

Ovulation (2)

Pituitary gland is associated with what hormone?

FSH (follicle stimulating hormone), and LH (lutenizing hormone)

What occurs in the secretory phase of the menstrual cycle?

Glandular and vascular changes in endometrium, primarily under the influence of progesterone, absence of fertilization results in fall of estrogen and progesterone and subsequent menstruation. Endometrium is thickest during this phase.

Hypothalamus is associated with what hormone?

GnRH (gonadotropin releasing hormone)

Hypothalamus releases

Gonad Releasing Hormone (GnRH or GnH)

The dominant follicle is aka

Graafian follicle

What are the cons of HRT?

Increases the risk for breast cancer, uterine cancer, and ovarian cancer. Increased risk of blood clots and heart attacks.

Ultrasound Appearance of Graafian follicles

Large anechoic, cyst like structure measuring ~1.8-2.5 cm directly before rupture / ovulation. May see cumulus oophorus: a small "bubble" within the follicle, budding from inner wall.

Ovulation ultrasound appearance

May see small amount of fluid (blood or liquor folliculi) collected in the posterior cul de sac

What are the phases of the menstrual cycle?

Menstrual phase, proliferative phase, and secretory phase

What denotes completion of the secretory phase?

Menstruation

What is mittelschmerz?

Midcycle pain associated with ovulation.

Ultrasound Appearance of growing follicles

Multiple small anechoic follicles begin to develop (~day 1-5)

What is the ultrasound appearance of the ovaries of an individual using hormonal birth control?

Non dominant follicles only, endometrium is a thin echogenic line

FSH (follicle stimulating hormone) causes

Numerous follicles in ovary to grow.

A consistent menstrual cycle longer than 35 days indicates

Oligomenorrhea

When should follicles be measured?

Only if large or in patient undergoing treatment to induce ovulation

What denotes the end of the proliferative phase of the menstrual cycle?

Ovulation (1)

Rising estrogen levels released by developing follicles trigger

Pituitary gland to release luteinizing hormone (LH)

Rise in GnRH causes ________ to release ___________

Pituitary gland; follicle stimulating hormone (FSH)

A consistent menstrual cycle less than 21 days indicates

Polymenorrhea

Secretory phase of menstrual cycle is associated with

Progesterone

What occurs in the proliferative phase of the menstrual cycle?

Regrowth of the endometrium mainly under the influence of estrogen. Estrogen is released by the ovarian follicles.

How does the menstrual cycle relate to the lunar cycle?

Similar length, women often "sync with the moon" where mensus commonly occurs around full moon (or new moon)

What is HRT used to treat?

Symptoms of menopause including hot flashes, mood swings, sleep disorders, vagina dryness.

What occurs to the remaining follicles that did not become Graafian follciles?

The undergo atresia and form scar tissue (corpus albicans)

Ultrasound Appearance of corpus luteum

Thick hyperechoic wall, "ring of fire" on color doppler.

The Graafian follicle ruptures through what at ovulation?

Tunica albuginea (and germinalis epithelium)

Dysfunctional Uterine Bleeding (DUB) is

Vaginal bleeding not related to the menstrual cycle

HRT is aka

hormone replacement therapy