How perimenopause causes lighter or heavier periods

Like other perimenopause side effects, the heaviness of your period is something you can expect to change over time. As your period becomes longer or shorter as your cycle changes, your flow may also become heavier or lighter. Since estrogen and progesterone change during perimenopause, this can cause your body to produce irregular periods. 

How perimenopause disrupts your flow

During perimenopause, ovulation doesn’t occur every cycle. Because of this change, your ovaries produce less progesterone after ovulation (considering you’re not pregnant). “The most important role of progesterone is to get your uterus ready so that it can receive, implant, and support a fertilized egg during pregnancy,” according to the University of Rochester Medical Center

Heavy flows: When less progesterone is produced, the lining of the uterus builds up for longer and can cause heavier flows. High estrogen levels can also thicken the lining of the uterus, which results in more blood. 

Lighter flows: Bleeding may become lighter and shorter as estrogen levels drop and your uterine lining is thinner. 

Managing different flows

Birth control can stop menstruation completely and hormone therapy can prevent ovulation, which can make periods lighter and shorter. But if you don’t want to go on medication, you have other options.

Heavy flows: Wear an absorbent period underwear or menstrual cup for heavier period days. 

Lighter flows: Wear a panty liner or thin pad instead of a tampon because there won’t be enough blood to absorb.

It’s common to miss a period completely during perimenopause. You might also notice spotting between periods. 

Reviewed by the Ovia Health Clinical Team


Chad Haldeman-Englert, Maryann Foley, Raymond Turley. “Progesterone”. University of Rochester Medical Center. University of Rochester Medical Center.

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