smiling group of women
smiling group of women

Is Period Syncing A Myth?

Posted on October 7, 2019 by Henry Ford Health Staff

Some women will swear by it. Period syncing seems to be the obvious explanation for your menstrual cycle lining up with other women around you. From coworkers you see every day and sports teams you practice with to family members and housemates you live with, most women will claim they have experienced period syncing before.

The concept of period syncing came about after a study conducted at a women’s college dorm in the 1970s by bio-psychologist, Martha McClintock. McClintock is famously known for discovering human pheromones – chemicals created by the body that affect our social and sexual behaviors. This study, known as the McClintock Effect, found that there seemed to be a relationship between your menstrual cycle and spending extending amounts of time with other women.

So, if a scientific study supports this concept than it must be true, right? According to Melodee Babcock, a certified nurse midwife at Henry Ford Health, that’s not quite the whole picture.

Unpacking the Myth

“There are some research controversies as to whether or not menstrual syncing is real,” says Babcock. “For example, there are many critiques on how these studies have been conducted.”

The McClintock Effect isn’t the only theory used to explain period syncing. Many believe your menstrual cycle is related to lunar cycles or that your period aligns with the most dominating personality type in your life. Ultimately, there just isn’t enough concrete evidence to support these claims.

Additionally, there have been recent studies showing that menstrual syncing probably happens by chance.

“The average menstrual cycle lasts about 28 days, with an average bleed time of 5 days,” says Babcock. “The odds that your period occurs within a few days of other women around you are fairly high.”

Think of period syncing more as a social construct. When your cycle doesn’t line up with other women, you probably don’t notice it. However, when it does, you are more likely to remember that. This helps to reinforce female bonding, the need for close female relationships and our connection to nature. Above all, it helps to normalize menstruation – a natural function that has been stigmatized as being unclean or shameful in the past and still can be in some cultures and parts of the world.

Explaining Changes in Your Cycle

While period syncing may not be a scientific explanation for your menstrual cycle irregularities, there are many factors that can contribute to the length of your cycle or if you have a period at all. These include:

It is important to note that many forms of birth control can cause you to not have your period or to only have short, light periods.

“It is not medically necessary to have a period if you are taking birth control to control your bleeding,” says Babcock. “However, even with perfect use there is still a risk of pregnancy, and you should take a home pregnancy test if you miss a cycle."

You should consider seeing a certified nurse midwife or your OB-GYN if you have less than 8 menstrual cycles a year, have spotting or bleeding between periods, or extremely heavy or painful periods.

To find a doctor who specializes in women’s health or a certified nurse midwife at Henry Ford, visit or call 1-800-HENRYFORD (436-7936).

Melodee Babcock, CNM, is a certified nurse midwife, seeing patients at Henry Ford Medical Center – Livonia and Henry Ford West Bloomfield Hospital.

Categories : FeelWell

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