What You Need To Know About Menstruation

by Amy, RN, BSN

If you're a teenage girl you probably have started having a period. If not, are you anxious about the subject or worried that it might not happen? This whole menstruation thing might be a big mystery to you, it is to many women. It's actually very complex but, you will see that you need not be overly concerned if you haven't gotten it yet.

Menstruation is the outward proof that a girl is becoming a woman, so she needs to acquire an understanding of what happens during the menstrual cycle. Your period is not a downer, you're becoming a woman and women are very cool and important people. Having a period is your body's way of saying it is normal and functioning properly.

During puberty, hormones from the brain that stimulate the ovaries are released. The ovaries then produce estrogen and progesterone -- hormones that cause the eggs in the ovaries mature so the woman can become pregnant when she chooses to. Here's how the process goes:

Each month, one egg leaves one of the ovaries on its way to the uterus by way of the fallopian tubes. Meanwhile, in preparation for the egg, the uterus starts to develop a thicker lining so that the walls become cushion (the endometrial lining). If the egg reaches the uterus and is fertilized by sperm, it attaches to this cushiony wall, using the extra blood and tissue to nourish itself as it slowly develops into a baby.

Most of the time the egg just passes right through without fertilization. It dissolves. Since the uterus no longer needs the extra blood and tissue which made the walls thick, it sheds them through the vagina. This cycle will happen nearly every month until the ovaries stop releasing eggs, usually several decades later.

Periods are different for every woman. Some girls start menstruation when they're 9 or 10, some in their late teens. The length of the cycle also varies. Some girls periods last longer than 28 days, some shorter. If you have just begun your menstruation, your body will need time to regulate itself to these changes. So your periods might be a bit erratic at first. You may have two cycles in one month and miss having one the next month. How long the period lasts varies also. Some girls have their periods for only 2 or 3 days, others as long as a week. The menstrual flow of blood can vary from woman to woman also.

Some girls may have body or mind changes that they notice around the time of their period. Menstrual cramps are pretty common during the first few days of their periods, most likely caused by prostagladins that causes the muscles of the uterus to contract. These cramps tend to become less uncomfortable and sometimes even disappear completely as a girl gets older. Over-the-counter pain medication like ibuprofen or acetaminophen can give relief; if not, a health care provider can help.

As your period approaches, you may experience premenstrual syndrome (PMS). You may find your emotions amplified during this time. Many women get depressed, easily irritated, angry, and others cry more than usual or get cravings for certain foods. PMS is related to changes in hormones. Hormone levels rise and fall during a menstrual cycle, affecting the way she feels, both mentally and physically.

Emotions can be more intense, and many women may feel bloated or puffy because of water retention. When your period begins, PMS usually goes away. You may also have an acne flare-up. Periods are a complex part of puberty, but also your body's way of telling you it is functioning properly and you have taken good care of it. Your life won't change that much. You can still exercise and do everything you enjoy. If you have any questions about periods, ask a parent, health teacher, health care provider, or nurse. You can also ask friends or sisters who have had their period for a while. In time you will see that periods are a normal and routine part of your life.


The Menstrual Cycle

The "typical" menstrual cycle occurs regularly over 28 days. Most women have cycles with an interval that lasts from 21 to 35 days. Frequently cycles are unusually short or long during adolescence.

(Day 1 to About Day 14 in a 28-Day Cycle)

The Menstrual Phase
The first day of your menstrual period is considered Day 1 of your cycle. The menstrual phase includes your period. During this time, the endometrium (the built-up lining of the uterus) is shed, along with a little blood. Many of the problems that women experience with their menstrual cycle occur during this phase. For example, some women experience menstrual disorders such as dysmenorrhea (painful periods) or menorrhagia (unusually heavy periods).

The Follicular/Proliferative Phase
During the proliferative phase, the body produces a hormone called follicle-stimulating hormone (FSH). Follicle-stimulating hormone promotes the growth of a follicle (egg sac) within the ovary. An ovum (egg) matures in the follicle during the proliferative phase. FSH also stimulates the ovary to produce increasing amounts of estrogen. In turn, the estrogen causes endometrial tissue to build up (or proliferate), lining the interior of the uterus.

(About Day 14 in a 28-Day Cycle)
The mature ovum bursts from the follicle about midway (approximately 2 weeks before onset of next menstrual period) through the menstrual cycle. This process is known as ovulation. The ovum then travels from the ovary down the fallopian tube, and into the uterus.

The Luteal/Secretory Phase
Once the ovum has been released, the follicle becomes a sac known as the corpus luteum ("yellow body," because it contains yellowish, fatty matter). A hormone called luteinizing hormone (LH) causes the corpus luteum to grow and to secrete progesterone, another female hormone.

During the secretory phase, progesterone makes the endometrial lining stronger and spongy in texture. Progesterone also stimulates glands in the endometrium. These glands produce uterine fluid, and their purpose is to support embryonic development if fertilization has occurred at or around the time of ovulation. It is in this phase of the menstrual cycle that women who suffer from premenstrual syndrome (PMS) may begin to experience their symptoms. Generally symptoms are worse during the last seven to ten days of the cycle, ending at or soon after the start of the menstrual period. In a woman who hasn't become pregnant, the level of progesterone peaks about a week after ovulation and then begins to drop along with the estrogen level. The flow of blood to the endometrium decreases, and its upper portion is broken down and shed during menstruation. At the same time, the corpus luteum withers.

The dip in estrogen and progesterone at the end of the cycle help let the body know that it's time to start the cycle all over again. The menstrual cycle doesn't have to be a drag, it actually shows how complex your body is and a sign that it is functioning properly! Congratulations, you are a woman and being a woman is terrific!

The Charts

The Ovarian Cycle chart shows the maturation and deterioration of the ovum and how it occurs every month.

ovarian cycle

The Endometrial Cycle chart shows how the endometrial lining builds up during the normal menstrual cycle and then is broken down and shed during menstruation (menses). Meanwhile at the same time back at the Ovarian Cycle chart, the corpus luteum withers.

endometrial cycle

Aren't women amazing! The menstrual cycle is actually a very cool and very complex process that results from the many parts of the body working together. The brain, the ovaries, the adrenal glands and even the thyroid, all have to come together with their different hormonal and chemical influences. I guess you could say it is kind of like a small orchestra in your body.

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