How to tell if your menstrual cycle is normal — and what to do if it's not (2024)

• A period normally lasts between two and seven days, with the average period length being five days.
• If your period lasts more than eight days and you are experiencing heavy bleeding, see a doctor.
• To determine if your period is irregular, track your menstrual cycle with an app or paper calendar.

How long a period lasts will depends on various factors including your lifestyle, genetics, and age.

On average, periods last between two and seven days, with the average period being five days. However, that length can vary depending on your stress levels, diet, and other factors.

In fact, an estimated 9% to 15% of menstruating persons will experience an irregular period at some point in their life. But that's not always a cause for concern.

Here is how to tell if changes in your menstrual cycle are normal.

Signs your period is normal

There really is no such thing as a "normal period" as bleeding duration, heaviness, and timing differs from person to person. It's also totally normal for your period to vary a bit each month. However extreme fluctuations, like if it lasts more than eight days or you skip 2 or more months, may be cause for concern.

According to Rachel Bowman, MD, an assistant professor in the department of women's health in the Dell Medical School at the University of Texas at Austin signs of a typical menstrual cycle are:

• It happens every 21 to 35 days
• Bleeding lasts for two to seven days
• Initial bleeding is light
• A period is heavier on the second or third day, but then lightens again

Although all of those factors contribute to a "normal cycle," if your menstrual cycle doesn't check all these boxes, don't stress about it too much. There are many reasons the timing, duration, and bleeding patterns of your period might fluctuate. These includes:

• Age: It's common for your period's duration and bleeding patterns to fluctuate during adolescence before you settle into a pattern. Meanwhile, in your 40's as you near menopause, you might begin to skip periods or have periods closer together.
• Birth control: Some hormonal contraceptives, like the combined birth control pill, hormonal IUDs, the shot, and the implant may delay or stop menstruation. Interestingly, these hormonal products are often used to regulate or lighten periods.
• Medications: Certain medications, like antiepileptics, antipsychotics, and blood thinners can cause periods to become irregular.
• Lifestyle choices: Things like increased stress, smoking, or alcohol consumption can alter your cycle. Major weight changes can also disrupt your cycle.

Signs of an irregular period

A typical cycle lasts anywhere from 21 to 35 days. Therefore, anything outside of that window — whether your cycle is shorter than 21 days or longer than 35 — is considered irregular, says Bowman.

Bleeding or spotting between periods can also be considered irregular, says Jessica Geida, DO, an OB-GYN at Axia Women's Health.

Additionally, "if your cycle is fluctuating more than three days every month — say it is 22 days apart during one cycle and then 31 days apart from the next — that's a sign that you may have an underlying issue," says Bowman.

Some underlying health conditions associated with abnormal periods include:

• Pregnancy
• Eating disorders, like bulimia or anorexia nervosa
• Polycystic ovary syndrome (PCOS)
• Bleeding disorders, like hemophilia or von Willebrand disease
• Thyroid disorders

If your period is consistently more than eight days and you are experiencing heavy bleeding or pain you should see a doctor, says Bowman.

If you are experiencing irregular periods, your doctor may recommend regulating your period through hormone supplements, like birth control pills. "Birth control pills won't cure an underlying issue, but they can help [regulate your hormones which will help] with predictability and quantity of bleeding," says Bowman.

To determine if you have a regular or irregular cycle, try tracking your period.

Insider's takeaway

Regular periods occur every 21 to 35 days and last two to seven days. However, there are many factors that can influence your menstrual cycle, like certain medications and hormonal birth control.

If you have irregular cycles or if you are experiencing abnormally heavy bleeding or pain during your period, check in with your doctor to rule out potential underlying health conditions, like pregnancy, thyroid problems just a general and temporary disruption of your normal cycle.