This is why your period blood smells, according to a gynecologist

I remember my first period like it was yesterday. I was 11 years old, and it was July 4th—yes, Independence Day. I went to the restroom, saw the blood, and calmly stuffed my underwear with tissue. I went to my mom’s room, but the door was closed because she was on the phone. I knew not to interrupt grownups when they were speaking, so I hesitated before deciding to knock. Rightfully so, because my mom had no intention of prematurely ending her conversation until I said, “I got my period. Can I have a pad?”

She immediately hung up the phone and freaked out—in a good, excited way. I didn’t get it. It was just period blood, right? Not quite.

Periods. Such a beautifully complex experience. It’s a not-so-friendly reminder of the power our bodies have—the power to create life. A power that comes with period poop, period skin, pain, and of course—that delightful period blood smell.

To learn more about the how and why about period odor, I reached out to Dr. Jessica Shepherd, an ob-gyn and women’s health expert. Yes, we may have accepted the smell, but wouldn’t it be great to understand it a little better?

First things first, why does period blood smell?

“Menstrual blood smells different due to the fact that the blood is more than just blood,” says Dr. Shepherd. She said it consists of “bacteria, vaginal mucus, fluid, and tissues”—all of which contribute to the odor that comes with periods.

The intensity of the odor is dependent on “whether it’s ‘old’ or ‘new’ blood, which really just means how long it may have been inside the uterus before coming out,” Dr. Shepherd tells HG. Have you ever noticed brown blood down there? That’s just blood that has oxidized after being exposed to air for a long period of time, aka “old” blood. Blood that, according to Dr. Shepherd, “can cause a more intense smell.”

“Blood can be different—more or less intense depending on length of flow, volume of flow, and also whether it’s bacteria mixed with old blood or it’s bacteria in the vagina that’s coming out with the blood,” she says. “Either way, every woman has a different composition of her menstrual blood flow and that makes your period blood odor special and specific to you.”

When should we be concerned?

If your period blood smells strong and fishy, that might be cause for concern. Dr. Shepherd says that kind of odor can indicate an infection, like bacterial vaginosis. “Bacterial vaginosis can either go away on its own or be treated with antibiotics,” she adds. “If any woman has an out-of-the-ordinary odor, she should consider talking to her doctor.”

Is there any way to minimize period odors?

While period smells are totally normally, there are things you can do to make them less intense. “The best way to minimize any scents is to keep the areas as dry as possible to help reduce it if it’s bothering you,” says Dr. Shepherd. She recommends wearing cotton underwear, reducing the trapping of sweat with tight clothing or leggings, and changing pads or tampons more often if the smell is bothering you.