Fact checked by Sarah Scott

Key Takeaways

• A new study tested period products with real blood for the first time and found that many of the products either had a much lower or higher capacity for blood than what was advertised.

• The inconsistencies could make it hard to determine whether someone has menorrhagia, the medical term for heavy menstrual bleeding.

• You may have menorrhagia if your period lasts for more than seven days, or if you need to change your tampon or pad in less than two hours. You may also feel unusually weak or have extremely painful menstruation.
  

No one really tested the absorbency of menstrual products with real period blood before—not even the manufacturers themselves.

Many consumers were shocked by a recent study published in the journal BMJ Sexual and Reproductive Health, which found that most period products had either a much lower or higher capacity for blood than what was advertised. Researchers tested tampons, sanitary pads, menstrual cups and discs, and period underwear.

If you have heavy menstrual bleeding, also known as menorrhagia, you might have periods that last for more than seven days or require a change of tampon or pad after less than two hours.

Health guidelines recommend counting how many pads or tampons you use in order to track menstrual flow. But this method is likely inaccurate because of the discrepancy between the advertised absorbency of period products and reality. So how can you tell when you should seek medical attention?

Another sign of menorrhagia is passing blood clots the size of a quarter or larger. Or, you might feel unusually weak from excessive menstrual blood loss, according to Melanie Bone, MD, an OB-GYN and medical board member of the gynecological health company Daye.

In addition to abnormal amounts of blood loss, heavy menstrual bleeding is typically associated with extremely painful menstruation, Bone added.

While women's pain is frequently dismissed, excruciating pain that holds you back from daily activities, especially when accompanied by heavy bleeding, may signal that something else is wrong.

"It’s important to note that heavy menstrual bleeding can be a symptom of a condition associated with secondary dysmenorrhea or chronic gynecological disease," Bone said.

Dysmenorrhea, the medical term for menstrual cramps, can be either primary or secondary. While primary dysmenorrhea refers to recurrent pain from menstruation itself, secondary dysmenorrhea is caused by a preexisting health condition such as endometriosis, adenomyosis, or fibroids.

Endometriosis and Menstrual Cramps

Endometriosis is the most common cause of secondary dysmenorrhea. It can feel different for everyone, but pain is the most common symptom. About 80% of people with endometriosis have chronic pelvic pain. Other symptoms include painful sex, painful urination, painful bowel movements, nausea, fatigue, and severe bloating.

Ultimately, if your menstrual bleeding or pain level interferes with your daily activities, including school, work, or sports, Bone said that's a sign to seek medical attention.

Since the absorbency and performance of menstrual products like pads and tampons can vary, Bone added, period products may not adequately handle heavy flow or give you an accurate idea of how much you're actually bleeding.

"It underscores the importance of product testing to ensure that products meet the needs of all individuals," Bone said.

What This Means For You

If your period lasts longer than seven days, causes excruciating pain, requires a new pad or tampon more often than every two hours, makes you feel unusually exhausted or weak, causes you to pass blood clots, or interferes with your ability to do regular daily activities, talk to your healthcare provider about whether you have heavy menstrual bleeding.

Read the original article on Verywell Health.