Looking at a healthy cycle

A normal menstrual cycle is like a complex work of art (check out Figure 5-1). Okay, you may not think that when you're changing pads or dealing with cramps, but your reproductive system really is amazing. And yet many women understand little of the menstrual cycle. When you understand all the intricate workings, you have a much better grasp of how endometriosis can gum up the works, so to speak.

What exactly is the menstrual cycle anyway? Is it just the time you're actively bleeding, or is it the time between bleeds, too? When your doctor starts asking questions about your cycle, you may not be sure exactly what he's asking. Our goal is to translate that jargon into regular talk for you.

How long is the cycle?

When your doctor asks you how long your cycles are, he wants to know the number of days between Day 1 of one period and Day 1 of the next. Menstrual cycles are traditionally 28 days. However, only one in ten women actually experience regular 28-day cycles. Cycles are usually 21 to 35 days apart.

Day 1 of your period is the first day of full flow. If you spot on and off for a few days before breaking out the pads and tampons, you haven't started your new cycle yet. Even when you start a full flow period just before bedtime, it's still Day 1 of your new cycle.

Uterus Ovary

Fallopian tube

Figure 5-1:

A healthy menstrual cycle.

Uterus Ovary

Fallopian tube

Figure 5-1:

A healthy menstrual cycle.

Endometrium is shed as menstrual fluid.

Haematoma Fallopian

The egg is released into the fallopian tube.

The egg, if unfertilized is shed.

Endometrium continues thickening.

Endometrium is shed as menstrual fluid.

The egg is released into the fallopian tube.

The egg, if unfertilized is shed.

Endometrium continues thickening.

The most consistent element of the menstrual cycle is that periods start 13 to 14 days after ovulation. (Check out Chapter 7 for more about ovulation.) If you ovulate early (before day 14), your cycles are shorter than normal. If you ovulate later than 14 days into your cycle, your cycles are longer than 28 days.

When your doctor asks how long your period lasts, he wants to know how many days your bleeding lasts. Menstrual flow normally lasts two to seven days, with an average of four days.

How do hormones orchestrate your cycle?

So what regulates all this flow? The answer is hormones. When you're feeling out of sorts and irritable, you may say you're feeling hormonal, but the truth is that you're hormonal all the time. Estrogen goes up, follicle-stimulating hormone (FSH) goes down . . . your body constantly has something happening hormonally. The three hormone-control systems that work together to manage your cycle are

I The hypothalamus (the small structure in the middle of the brain that regulates the nervous and endocrine systems)

I The pituitary (an endocrine gland at the base of the brain below the hypothalamus that secretes several hormones)

I The ovary (the female reproductive organ that produces estrogen, progesterone, and eggs)

Right before your period starts, your hormone levels drop to their lowest levels. At this moment, the cycle starts again. (Check out Figure 5-2.)

Anterior lobe of pituitary gland

Figure 5-2:

The rise and fall of hormones during your menstrual cycle.

Anterior lobe of pituitary gland

Estrogen

GnRH = Gonadotropin-releasing hormone LH = Luteinizing hormone FSH = Follicle-stimulating hormone

What are the steps in a normal cycle?

The following list describes the menstrual cycle:

1. The hypothalamus, the master gland, produces a gonadotropin-releasing hormone (GnRH).

This production tells the pituitary gland to start making follicle-stimulating hormone (FSH).

2. FSH travels through the bloodstream to the ovaries.

3. Anywhere from 1 to 15 eggs containing follicles start to grow in the ovary.

One egg — sometimes two — grows faster than the others and becomes the dominant follicle or follicles. The rest stop growing and fade away, never to be seen again.

4. FSH stimulates the ovaries to produce estrogen, one of the main female hormones.

Estrogen helps the eggs mature and starts to thicken the uterine endometrial lining, which is very thin right after your period.

5. As estrogen rises, FSH is suppressed and then rises again in conjunction with the release of a luteinizing hormone (LH) from the pituitary gland.

This process occurs mid-cycle as the egg nears maturity.

6. LH causes the dominant follicle to enlarge and the egg to fully mature, weakening the follicle wall.

This causes the egg to burst out of its follicle in the process called ovulation.

7. The follicle that was home to the released eggs collapses.

Under the influence of the pituitary hormone LH, the collapsed follicle becomes the corpus luteum that produces progesterone. This progesterone then changes the composition of your endometrial lining, making it denser and more receptive to a potential embryo. Your basal body temperature rises one half to one degree when your progesterone rises.

8. The pituitary gland stops producing FSH so that no more eggs mature.

9. If no embryo implants, your estrogen and progesterone levels begin to drop ten days or so after you ovulate.

The uterine endometrium produces prostaglandins (see Chapter 3 for more about prostaglandins) that change the blood supply to the uterus and stimulate uterine contractions. The thickened lining now sheds as your menstrual period — a combination of blood, cells, and debris.

Normally, your endometrium is approximately 10 millimeters thick at the end of your cycle. The shedding, along with blood from the torn blood vessels, cervical mucus, endometrial tissue, and cellular debris, add up to a little more than 30 milliliters (an ounce) of discharge, although it certainly seems like a lot more! More than 80 milliliters (a little less than 3 ounces) of discharge is abnormal.

Menstrual blood normally doesn't clot, unless your flow is very heavy. Sometimes the lining is shed in large fragments (sometimes called decidual casts) that can look like an early miscarriage.

51 Tips for Dealing with Endometriosis

51 Tips for Dealing with Endometriosis

Do you have Endometriosis? Do you think you do, but aren’t sure? Are you having a hard time learning to cope? 51 Tips for Dealing with Endometriosis can help.

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