Menstruation 101: Understanding Your Menstrual Cycle

By EmpowHER April 25, 2011 - 9:55am

Menstruation and the menstrual cycle are often not well understood by many women, even though it is something they are faced with on a regular basis.

On average, the menstrual cycle is 28 days long, but just as all women are different, so are our periods. Normal cycles can range anywhere from 21 to 45 days in young teens and from 21 to 35 days in adults.

Many women may have heavy or irregular periods, making their periods unpredictable or otherwise difficult. Many women with irregular or heavy periods manage them with menstrual cups, which are safe to use right before you start your period and can be especially beneficial if your period is not quite as predictable as you’d like it to be.

The menstrual cycle timing described below is based on the average 28-day cycle. If your menstrual cycle is a bit shorter or longer, the timing of certain occurrences in your cycle may vary.

Day 1: Your menstrual cycle begins on the first day of your period, following the drop in the level of the hormone estrogen which signals your body to shed the blood and tissues lining your uterus.

Day 7: Bleeding (your menstrual period) has usually stopped by day 7. In the past week, your hormones have stimulated fluid-filled pockets called follicles to develop on your ovaries. Each follicle contains an egg.

Days 7 to 14: In the second week of your menstrual cycle, one follicle containing an egg will develop and reach maturity. A rise in your estrogen level starts to make the lining of the uterus grow and thicken to be ready if a fertilized egg implants there. This lining is very rich in nutrients and blood, and is able to nourish an embryo.

Day 14: If you have a 28-day menstrual cycle, day 14 is typically ovulation day – although this varies from woman to woman. If your cycle is shorter or longer, the exact day you ovulate may also vary slightly. During ovulation, hormones cause the mature follicle to burst and the egg is released from the ovary.

The egg takes a few days to travel down the fallopian tube. If the egg is fertilized with a sperm during these few days, it will continue toward the uterus and attach to the uterine lining. Since sperm can live in the body for three (3) to five (5) days, your most fertile time is considered to be about five (5) to seven (7) days – a few days on either side of your ovulation date.

Day 25 - 28: Estrogen levels will drop around day 25 if the egg is not fertilized. The egg breaks apart and is shed with the blood and uterine tissue during your menstrual period, which begins around day 28.

If you have any specific questions about or problems with your menstrual cycle or periods you should consult your healthcare provider.

NOTE: The above information on the menstrual cycle can be found on a visual timeline at WomensHealth.gov.