A 28 day cycle consisting of 3 phases during which the endometrium (inner lining of the uterus) Goes through certain changes to prepare for implantation of a fertilized egg.
Usually occurring on days 1 to 5
(The menstrual period, the curse (not recommended), big red, or
Aunt Red) Menstruation will begin on day 1 of your cycle and will
last between 3 to 8 days. Estrogen and progesterone levels fall
because the follicle that produced them degenerates. This causes
the blood vessels supplying the thickened wall of the endometrium
to constrict. This cuts off the blood supply causing the thickened
wall to fragment as the tissue dies. These tissue fragments along
with some blood empties out of the uterus and through the vagina.
Typically around a few tablespoons to about half a cup of blood
and tissue dribble out slowly during menstruation. The second day
of the menstrual flow is usually the heaviest. During and a few
days before menstrual flow one might experience cramps Ð slight
tight pains around the uterus. 4 to 5 days prior to the menstrual
flow women may start to experience Premenstrual Syndrome (PMS).
(This is what people refer to when saying, "It must be that time
of the month.")
The low levels of estrogen and progesterone during the menstrual phase, cause the hypothalamus (a part of the brain to produce GnRH (gonadotropin-releasing hormone). This hormone causes the pituitary to release FSH (follicle-stimulating hormone) and LH (luteinizing hormone). These hormones stimulate the growth of around 25 follicles inside the ovaries. The growing follicles release estrogen causing the eggs inside them to grow. This estrogen travels through the blood from the ovaries to the uterus, stimulating the repair and growth of the endometrium. As a result the endometrium becomes thicker and spongier. During this time usually only one egg and its surrounding follicle fully matures. At the end of the proliferative stage, this follicle bulges from the side of the ovary.
Around day 14 the mature follicle and a small spot on the surface of the ovary ruptures releasing an egg the size of a grain of sand. This process is called ovulation. The egg is funneled into the fallopian tube by petal-like projections called fimbriae, and proceeds down the fallopian tubes for the next 4 days. Inside the ovary, the remaining ruptured follicle seals itself and forms into a corpus luteum gland, which releases progesterone and estrogen. These hormones stimulate further growth of the endometrium and increase its blood supply, resulting in a healthy nutrient-rich environment for the possible implantation of a fertilized egg.
If
fertilization does not occur within about 24 to 36 hours after ovulation...
The rising levels of estrogen and progesterone from the corpus luteum
turn off the pituitary homornes, FSH and LH, which initially started
the growth of the egg. Since fertilization and implantation did
not occur, there is no embryo to release more hormones to sustain
the corpus luteum. As a result it degenerates, estrogen and progesterone
levels drop, and the new monthly cycle begins.
If
fertilization occurs within about 24 hours...
(see fertilization and pregnancy)
A
note on menstrual cycle irregularity
The first 1 to 2 years of menstruation during puberty is normally
irregular. This could mean differences from one period to the next
in the amount of blood flow, duration of the period, or length of
time between periods.
Once you've established a regular cycle, it can become temporarily irregular due to...
During a woman's forties, her ovaries produce less and less estrogen as her eggs run out. Usually between ages 45 and 55, her periods stop occurring.
Both of the following products function to absorb the blood and tissue from a period. Both are made of a clean soft cotton-like material. A pad (sanitary napkin) is an absorbent circular piece of material placed just outside the opening to the vagina. Most pads have a small adhesive area that sticks to the inside of your underwear. A tampon is an absorbent material that is placed inside the vagina using a plastic applicator that comes with the tampons. These products can be purchased at most drug or grocery stores. Most women carry either tampons or pads in a purse when expecting a period. You might consider carrying a pad in your purse as early as age 9 in case your first period starts away from home.
Commonly and sometimes rudely referred to as "that time of the month," as in, "it must be that time of the month."
Symptoms - these may not appear until a woman reaches her 20's or 30's
To reduce these symptoms...
If these suggestions don't help and the symptoms are too much for you, visit your doctor. Prescriptions for the pill can regulate your period.
Cramps
Most women at some time in their lives experience cramps (called
dysmenorrhea), characterized by pains in the lower abdomen or lower
back. These pains are actually caused by muscle contractions in
the wall of the uterus that squeeze the blood vessels supplying
the muscle, thus cutting off the muscle's oxygen supply, resulting
in cramping. This contraction is stimulated by the excessive secretion
of prostaglandins (a hormone involved in childbirth) one week or
two before your period begins. Typically cramps start 2 to 3 years
after a girl's first period. They are most common in women ages
17 to 25. By the late twenties or after giving birth many women
stop experiencing these cramps. 1 in 10 women find their cramps
severe enough to interfere with their day.
To reduce pain caused by cramps...