Your body
Managing your Period
What happens during the Menstrual Cycle
What is the menstrual cycle
The menstrual cycle is just that: a cycle. It is your body’s way of preparing itself for a possible pregnancy. Your hormone system controls your menstrual cycle. The changes in your body (including cramps, moodiness and your period) are brought on by changes in the levels of hormones that are running through your system. Your period – or the time of bleeding – happens when an egg has not been fertilized and your body gets rid of all its preparations for pregnancy.
What happens during the menstrual cycle?
There are three basic phases to the cycle:
Ripening (or the follicular phase): First, an egg starts ripening in your ovaries. At the same time the hormone called estrogen triggers the lining of your uterus (the endometrium) to thicken with blood and tissue in order to make a “cushion” for a potentially fertilized egg (an egg that has been fertilized by sperm). This happens during the first 14 days or so of your menstrual cycle. However, the process can be longer or shorter and each woman is different.
- The last 5 days of the follicular phase, plus your ovulation day are when you are most likely to become pregnant if you have sex without using some form of birth control.
- With ovulation, some women feel a bit of lower pelvic pain or have a tiny bit of red vaginal spotting. This is normal.
Premenstrual (or the luteal phase): When the egg is ripe, it leaves the ovary and starts traveling down the fallopian tubes. This is called ovulation and happens about 14 days after the last day of your period. During this time the hormone progesterone helps the estrogen keep the lining of your uterus thick and ready to receive a fertilized egg. If the egg is not fertilized (if it doesn’t hook up with active sperm), then the levels of the hormones that helped to thicken the lining of your uterus (progesterone and estrogen) drop, causing the lining to break down so that it (and the egg that was not fertilized) can be shed from your uterus. This is the end of the premenstrual period and the beginning of your period.
- The premenstrual period can happen any time from Day 7 to Day 22 of a normal menstrual cycle.
- It usually lasts about 13 to 15 days (from ovulation to the first day of your period).
- Most women have premenstrual symptoms of one kind of another. These include emotional symptoms – such as feeling angry, irritable, depressed or anxious – and physical symptoms – such as tender breasts, bloating, headaches or pimples.
- Sometimes these symptoms are so strong that they make normal day-to-day living difficult. This could be a sign of PMS (premenstrual syndrome) and you might want to make an appointment with your doctor to talk about treatment options that will help you.
Menstruation: This is the day you start to bleed. It is when the thickened lining of the uterus begins to shed that you have menstrual bleeding from your vagina. This is Day 1 of your cycle. While it may seem strange call this Day 1 – because it’s the end of the whole process – it is the only day that is easy to mark. A ripening egg or ovulation does not have any visible signs that are easy to track or notice. So the beginning of your period marks Day 1 of your cycle.
- Menstruation, or bleeding, can last from 2 to 7 days.
- Most of your menstrual blood loss happens during the first 3 days.
- This is also when you might have cramps and pain in your pelvis area, legs and back. This is because your uterus is contracting to help get rid of the lining. Cramps can be mild or severe.
- If your period seems too heavy and painful, you may want to see your doctor or ask a pharmacist to suggest an over-the-counter medication.
How long does a cycle last?
How do you track a cycle?
A cycle starts on the first day of your period and continues until the first day of your next period, when the cycle starts all over again. You can use a calendar to track your cycle. This helps you predict when your period is going to start (so you can be prepared), or when it should start (so you can talk to your doctor about any changes or the possibility of pregnancy). The easiest way to do this is to just use your regular calendar and mark a red P or a dot for the first day of your period. If you have settled into a regular cycle it should be easy for you to count the number of days (i.e., 28) and then pencil in when you will be expecting your next cycle to start.
Keeping a Calendar: You might also want to keep a more detailed calendar that includes the day of your last period and any symptoms you experience during your cycle – such as tender breasts, cramps, headaches, backaches, moodiness, acne, difficulty sleeping, tiredness, bloating or an upset stomach.
How long does a cycle last?
A cycle usually lasts about 28 days, but it can range anywhere from 21 to 36 days. The length of a cycle varies from woman to woman. It is usually not very regular during the teenage years and during the years before a woman begins to experience menopause (called perimenopause).
- When a young woman starts to menstruate, it usually takes a few years for her body to fall into a regular pattern of menstruation. It is normal for her cycle to be a little off schedule for the first few years.
- In the years leading up to menopause (when a woman stops ovulating and her period stops) a woman’s cycle may also be a bit unpredictable. During this time, menstruation may actually last a shorter period of time and the time between periods may be longer.
What is normal?
A “normal” menstrual cycle can be very different for different women. “Normal” can also change depending on your age. Long or unpredictable menstrual cycles are normal for teenagers and women in their 40s. If you are not a teenager or older than 40 and your cycles are shorter or longer than 21 to 36 days, it could be that you have an underlying problem and you should consult your doctor of a health-care professional.
Signs to look for:
If you experience any big changes in your cycle or in the amount of bleeding or pain (or other symptoms) that go with your period you should talk to a health professional. Some signs to look for include:
- Menstrual bleeding for 3 or more cycles that:
- Lasts longer than 7 days.
- Is heavier than normal (if, for example, you are passing large clots or soaking a large pad or tampon every one or two hours)
- Bleeding between menstrual periods.
- Pain in the pelvic area that is not linked to menstrual bleeding and lasts longer than a day.
- Emotional or physical symptoms (cramps, nausea, depression, irritability) that interfere with your daily life and are linked to your cycle.
Keeping a calendar will help you know when something is not quite right. It will also help you talk to your doctor or other health-care professional about your symptoms.
Last Modified: January 16, 2008
