Okay, so we have periods. Whether you refer to it as a “visit from Aunt Flow,” “that time of the month,” or one of the less polite euphemisms…they happen. The medical term for a period is menses, which is the Latin word for “months.” Many of us assume that a period happens monthly, but throughout our lifetime there is more variation than many realize.

What happens in the menstrual cycle is a process of making a thick, spongy, blood-filled lining within the uterus to prepare for the implantation of a fertilized egg. When a person becomes pregnant, the placenta attaches to this spongy lining and the fetus grows inside the uterus. If an egg is not fertilized, this lining is shed as a period.

There are four phases of the menstrual cycle:

  • Menstruation. This is your period. It typically lasts between 2 and 7 days. This is considered day 1 of your monthly cycle.
  • Follicular phase. During this time, ovarian follicles mature in preparation for one to burst and release an egg during ovulation. The follicular phase starts on day one and lasts until ovulation–approximately 13 to 14 days.
  • Ovulation. When an egg is released from an ovary. This lasts about 12 to 24 hours.
  • Luteal phase. This is the time between ovulation and the start of your next period when the lining of your uterus is thickening. It lasts between 12 and 14 days.

This process starts in puberty and repeats itself until most of a person’s healthy eggs have been given a chance to be fertilized—or when the natural biological process of menopause begins, most often between ages 45 and 55.

Your period as a teenager

What is a ‘normal’ menstrual cycle for teens?

The first period usually occurs around age 13 in the United States but can occur anywhere between 10 and 16 years of age. It may take several years before the menstrual cycle becomes a regular monthly event.

During this time, periods seem to happen somewhat randomly and the amount of bleeding or number of days of bleeding often varies as well. Puberty can cause irregular periods because of hormonal changes, and there is often no cause for concern. Usually around the ages of 16 to 18 most people who menstruate will begin to have regular periods.

Peak reproductive years: 20 – 40

At what age should periods be regular?

People who menstruate tend to have their most regular menstrual cycles during their peak reproductive years, between the ages of 20 to 40.

During the reproductive years, an average menstrual cycle is 28 to 35 days total and your period (or bleeding) lasts four to six days. It’s important to note the cycle isn’t the same for everyone.

How long should a period actually last? As far as what a “normal” period cycle is, it can range anywhere from 21 to 35 days with two to seven days of bleeding, which tends to be heaviest in the first two days. A small amount of bleeding at the time an egg is released from the ovary, usually 14 days before the onset of the next menses, is also considered normal.

Subtle changes likely: late 30s and 40s

At what age does your period start to change?

Those who menstruate may notice subtle changes in their menstrual cycles starting in their late 30s and 40s.

At first, you may notice shorter intervals between menses, and later, you may skip several cycles and/or have longer times without a period. These are common cycle changes and often the first signs of perimenopause.

Perimenopause is the two to eight years prior to menopause, and common signs may include hot flashes, mood changes or other symptoms of hormonal change. While you cannot “test yourself” for perimenopause, you should speak with our provider if you begin to notice changes in your cycle and you experience new symptoms.

The big change: menopause

What exactly is menopause?

Menopause officially is diagnosed when a person has been without a period for 12 months in the absence of other reasons. During menopause, the ovaries stop producing as much estrogen, the hormone that stimulates menstruation, so they no longer release an egg each month.

The median age of menopause is 51 years of age. One percent of females will undergo menopause before age 40 and two percent are still not menopausal at age 55. Those who smoke, have Type 1 diabetes, live at high altitudes, are undernourished or are vegetarian tend to undergo menopause at younger ages.

A family history of menopause before age 45 may also predict earlier menopause. There are no accurate blood tests to diagnose menopause, but other conditions that may cause irregular menstrual cycles can be excluded.

While the first sign of menopause on the horizon is usually a change in the normal pattern of your periods, the most common symptom is hot flashes.

Other causes of period changes or irregular periods

Besides age, there are many other reasons for irregular or missed cycles:

  • Pregnancy and breastfeeding naturally prevent the body from going through the menstrual cycle.
  • Contraceptive methods, such as extended-cycle birth control pills, Nexplanon, DepoProvera, or the Mirena IUD, may safely change how frequently someone menstruates–or stop it all together. These can also be used as a treatment for painful or heavy periods.
  • Extreme stress, such as a death in the family or midterm exams, can delay menses on rare occasions.
  • More concerning causes of irregular menses are excessive exercise, polycystic ovarian syndrome (PCOS), extreme weight loss or gain, uterine fibroids, uterine cancer and thyroid disease.

Know what is a normal healthy period–for you.

When should I be worried about my period changes?

While “abnormal” menstrual bleeding is quite common, the best way to know what is normal for you is to keep a record of when your period starts, how many days you bleed, whether the bleeding seems heavy or light, and whether you notice cramping or other symptoms. Three months of keeping track should be enough to get an idea of what normal is for your body.

Seek medical advice if:

  • Your periods suddenly stop for more than 90 days
  • Your periods become irregular after having been regular
  • You bleed for more than seven days
  • You bleed more heavily than usual (soaking through more than one pad or tampon every hour)
  • You bleed at random times between periods
  • You bleed more than a year after your last menstrual period (i.e., postmenopausal bleeding)

As always, if you have any questions or concerns about your menstrual cycle, contact a Women’s Healthcare Associates office to schedule an appointment.