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Your Menstrual Cycle: An Overview

Menstrual Cycle

What is the menstrual cycle?

The menstrual cycle is a monthly hormonal cycle the body goes through as it prepares for the possibility of pregnancy. The average young woman starts menstruating two years after her breasts begin to develop and pubic hair starts to grow. This is often around age 12, but can be a few years earlier or later.

Understanding how the menstrual cycle works is important for women of all ages. Reasons include helping you get pregnant, avoiding getting pregnant, understanding when something may be wrong, and managing menstrual symptoms.

How Long Does a Menstrual Cycle Last?

Your menstrual cycle starts on the first day of your period and ends the first day your next menstrual period arrives. The average menstrual cycle is 28 days long, but the length may vary or even change from month to month. If your periods come somewhere between every 24 to 38 days, your cycle is considered regular. However, if your cycle is longer or shorter, it’s a good idea to speak with your physician to find out what’s going on.

What is Ovulation?

Ovulation is a process that occurs in the middle of your cycle, usually near the 14th day. At this time, one of the ovaries releases an egg so that it can be fertilized by sperm and lead to pregnancy. You’re most likely to get pregnant in the three days leading up to and including ovulation. If the egg isn’t fertilized, the uterine lining sheds and you’ll get your menstrual period. It’s not uncommon to experience a bit of discomfort during ovulation, such as lower abdomen pain, spotting, or bleeding. But some women don’t experience any symptoms.

What Happens During Menstruation?

Menstruation is the part of your menstrual cycle when the endometrium that lines the uterus is shed and you get your period. This happens when an egg from your previous cycle isn’t fertilized and levels of the hormones estrogen and progesterone drop. The low hormone levels let your body know that it no longer needs a thick uterine lining to support pregnancy, and then sheds this blood, mucus, and tissue from the uterus through the vagina.

How Menstrual Cycles Change With Age, Missed Periods and Changes in Flow

Hormones are the messengers that regulate the menstrual cycle. The levels of our hormones change during different phases of our lives, causing the monthly bleeding we experience to change too.

Most girls have irregular periods during puberty and it can take up to three years for a girl’s period to become regular as hormones balance out. Going on or off birth control, switching birth control methods, or having a baby can cause changes in your flow or the length of your period. Changes in flow could also be caused by extreme stress, consistent over-exercising, or an eating disorder.

Due to changing hormone levels and unpredictable ovulation, you can expect to experience some period irregularity during perimenopause. Around your 40s, your ovaries produce less estrogen, so your periods may get shorter and lighter, or less frequent. How menopause affects the menstrual cycle is rarely the same from woman to woman. Some women don’t experience any intense symptoms, while others are greatly affected by things like heavy bleeding. Some women will experience inconsistent periods for months or years, whereas others see their menstruation end more suddenly.

It’s best to mention any missed periods to your ObGyn provider.

Learn more:

If you would like to meet with a knowledgeable doctor, consider contacting Women’s Health Arizona. As Arizona’s largest ObGyn group, we’re trained and solely dedicated to delivering the best ObGyn experience in convenient and comfortable settings around Phoenix.

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