Why You May Experience Gas Before Your Period

Smelly gas before your periods may not be pleasant, but it's perfectly normal—and here's why.

Cramps, breast tenderness, bloating, trouble sleeping, and increased appetite are more than enough premenstrual difficulties for one individual. However, extra gas before and during your period can also be part of your monthly cycle.

PMS Symptoms

The Office on Women's Health (part of the U.S. Department of Health and Human Services) lists a number of the symptoms of premenstrual syndrome (PMS), including gastrointestinal (GI) symptoms such as constipation, diarrhea, bloating, and gas. Hormonal changes are likely to blame for the discomfort.

A study from the journal BMC Women's Health in January 2014 found that 73% of individuals surveyed experienced at least one gastrointestinal symptom before or during their periods. While abdominal pain and diarrhea were the most common, this study demonstrated that GI symptoms are common before and during periods.

Why Gas Smells So Bad

Abbe Wain, MD, assistant professor of obstetrics, gynecology, and reproductive science at Icahn School of Medicine at Mount Sinai in New York City, explained why gas before a period might be worse. Dr. Wain said that plenty of patients have complained of way worse gas when menstruation is about to start.

Dr. Wain said different theories explain why period farts happen. A lot of it has to do with why farts smell in the first place.

Farts are a "healthy, natural, and normal byproduct of digestion," Ana Tuyama, MD, a gastroenterologist with New York Gastroenterology Associates, said.

Though accidental farting can embarrass you, it doesn't usually mean something's wrong with your health—even if it's stinky. "Smelly gas is usually the result of bacterial fermentation of food/stool matter in the colon," Dr. Tuyama said. Normal gut bacteria feast on the foods you eat and produce stinky sulfur-containing compounds.

"Smelly gas is often associated with consuming a fiber-rich diet that includes foods high in sulfur," Dr. Tuyama said. And plenty of healthy veggies fall into this category.

Why Gas May Be Worse Before Your Period

As ovulation approaches—roughly day 13 or 14 of your menstrual cycle—levels of the hormone progesterone begin to rise "in preparation for a possible pregnancy," Texas-based ob-gyn Heather Bartos, MD, said. During pregnancy, progesterone contributes to a "lazy gut," Dr. Bartos noted, resulting in constipation, burping, and morning sickness.

But if you don't get pregnant and get your period, the GI floodgates open. "It's not your imagination if you get diarrhea when your period first starts," Dr. Bartos said. During PMS week, "everything was held in" by progesterone, Dr. Bartos noted, and now it's exiting.

Compounds called prostaglandins are also released when you get your period; they prompt the lining of the uterus to shed, Dr. Wain said. Prostaglandins cause period cramps and make smooth muscle "more motile," Dr. Wain said.

In simpler terms, prostaglandins don't just make you feel pain from uterine cramps; they also get your colon moving—leading to farts and loose stools.

"In the digestive tract, prostaglandins can cause smooth muscle contractions leading to enhanced gastrointestinal pain, distention, and sometimes diarrhea," Dr. Tuyama said. When prostaglandin production goes up, bloating and farting do, too. (Fun prostaglandin fact: Ibuprofen works against the compound; it's why Motrin or Advil might help alleviate your cramps.)

What You Can Do About Gas Before Your Period

If period farts plague you, try consuming primarily unprocessed whole foods in the days leading up to tampon time, Dr. Bartos said.

"Going cleaner with your diet, gas tends to get better, plant-based foods tend to move better through the system, and you can feel like your symptoms are nearly gone," Dr. Bartos said. It's probably a good idea to stick to easy-to-digest foods before your period, too. In other words, beans and cauliflower will only worsen a stinky situation.

Please don't be too embarrassed or nervous to talk to your healthcare provider if you think a food intolerance or something more serious could be behind your gas. If you already have sensitive intestines—say, irritable bowel syndrome or inflammatory bowel disease—you may find that menstruation worsens things.

If you're pretty confident you're dealing with normal, albeit extra smelly period farts, there's really no reason to do anything about it. As Dr. Bartos said: "If you're not bothered by it, who cares?" Exactly.

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