It’s tough to define “normal” when it comes to the amount of bleeding you experience during your period.
That’s because there’s a lot of person-to-person variation in terms of volume. And talking about specific quantities—like the number of milliliters the average woman loses—won’t really help you figure out if your bleeding is heavy, says Judi Chervenak, M.D., an ob-gyn at New York City’s Montefiore Medical Center.
“Menstrual periods are considered heavy when they last longer than eight days, or involve bleeding through more than two pads in an hour for four hours in a row,” says Nanette Santoro, M.D., chair of obstetrics and gynecology at the University of Colorado Denver.
“Really, the most important thing to ask yourself is if there’s a change in your bleeding—if it’s heavier than your norm,” adds Chervenak. If the answer to that question is yes—and especially if you notice fatigue, weakness, light-headedness, or heart palpitations—you should let your doctor know ASAP. “It could be nothing, but it could also be a sign of a lot of different underlying issues,” says Chervenak. (Want to pick up some healthier habits? Sign up to get healthy living tips and more delivered straight to your inbox!)
What kind of issues? Here are five.
These are small, benign (non-cancerous) tumors that form in the muscle wall of the uterus, explains Santoro. Up to 70 percent of women will experience one or more of them before age 50, and heavy menstrual bleeding is the most common symptom of a fibroid. Spot bleeding between periods, cramps, and lower-belly pain are also symptoms, according to the U.S. National Library of Medicine. Depending on how many fibroids you have and their placement, treatments range from doing nothing to a hysterectomy.
These are grape-like growths that branch off from the lining of your uterus, says Chervenak. They’re often harmless, but they can cause infertility or miscarriage, according to the Cleveland Clinic. While they can cause heavy bleeds, they’re more often associated with irregular periods or bleeding between periods, says Santoro. Your doctor may want to remove them, or she may prescribe drugs to treat the kinds of hormone imbalances that cause polyps to form.
“This is basically an overgrowth of the endometrium, or the lining of the uterus,” says Chervenak. In some cases, hyperplasia can increase a woman’s risk for uterine or endometrial cancer, she adds. Again, hormone imbalances could be to blame. A surplus of estrogen without sufficient progesterone can lead to hyperplasia, and as a result it’s more likely to strike women after menopause, when ovulation stops and your body no longer makes progesterone, says the American College of Obstetricians and Gynecologists. Treatment usually involves drugs to correct hormone shortages.
Any condition that messes with the way your blood is supposed to clot or flow could lead to heavy menstrual bleeding, says Chervenak. There are a lot of these conditions, but a common one is von Willebrand disease (VWD), which affects two to four million Americans. VWD is a hereditary condition, and people who have it are missing a specific type of blood clotting protein. Bruising easily and suffering nosebleeds are associated symptoms, according to the National Institutes of Health.
If any one of several hormones is out of whack, that could lead to heavy bleeds. “Estrogen builds up the lining of the uterus, while progesterone stabilizes that lining,” says Chervenak. If there’s an imbalance between the two, that could cause excessive bleeding. “It could also lead to uterine cancer,” she adds. Again, hormone-replacing or hormone-stimulating drugs can be effective treatment options.
Cancer, liver or kidney disease, endometriosis, infections of the pelvis, and thyroid disease could all cause unusually heavy bleeding, says Chervenak. “And of course, you can’t rule out pregnancy if a woman is of reproductive age,” she adds.
It’s pretty much impossible for a person to self-diagnose most of these conditions based on symptoms alone, she says. So bottom line, if you’re experiencing an unusually heavy period, see your doc.