It’s not your imagination — feeling gassy, bloated, or crampy right before your period is completely normal. This common premenstrual symptom affects many people due to natural hormone fluctuations that influence the digestive system.

Before your period begins, your body undergoes a series of hormonal changes that can impact how your intestines and colon work. These shifts may lead to extra gas, bloating, changes in bowel movements, and even smellier flatulence.

Let’s explore why this happens, what other digestive symptoms you might notice during your cycle, and how to ease discomfort naturally.

Why You Get Gassy Before Your Period

Hormonal changes play a big role in how your gut behaves during your menstrual cycle. The two main hormones involved are estrogen and progesterone, which rise and fall throughout the month.

As your period approaches, levels of both hormones shift dramatically. These fluctuations can slow down or speed up digestion — leading to gas buildup, bloating, and even diarrhea for some people.

According to Abbe Wain, MD, an assistant professor of obstetrics and gynecology at Mount Sinai, this process is closely tied to prostaglandins, which are hormone-like substances released right before your period begins.

Prostaglandins help your uterus contract to shed its lining. But they can also affect other muscles in your body, including the smooth muscles of your intestines, making them more active.

This can lead to:

  • Increased intestinal movement (motility)

  • More frequent bowel movements

  • Cramping or abdominal pain

  • Extra gas production

So when your uterus is working hard, your colon often joins in — which explains why many people experience gas, bloating, and loose stools in the days before or during their period.

How Hormones Affect Digestion

Your digestive system and reproductive hormones are more connected than you might think.

  • Estrogen can make digestion slower by relaxing muscles in the digestive tract. This may cause constipation and bloating earlier in your cycle.

  • Progesterone, which peaks after ovulation, tends to slow digestion as well, leading to a “lazy gut” effect.

  • When progesterone levels drop sharply before menstruation, digestion speeds up again — resulting in sudden bowel movement changes, including gas or diarrhea.

If you already have a sensitive digestive system, such as with irritable bowel syndrome (IBS), these hormonal changes may feel more intense.

People with IBS often report that their abdominal pain, bloating, and gas worsen right before or during their period because their intestines are already prone to spasms.

Other Gastrointestinal Symptoms During PMS

It’s not just gas — many people experience multiple digestive changes before their period.

A 2014 study found that 73% of women reported at least one GI symptom before or during menstruation. These include:

  • Abdominal pain or cramping

  • Bloating or fullness

  • Constipation

  • Diarrhea

These symptoms are considered part of premenstrual syndrome (PMS) and usually appear one to two weeks before your period, then improve once bleeding begins.

As Heather Bartos, MD, an OB-GYN in Texas, explains, progesterone “holds everything in” leading up to menstruation. Once hormone levels fall, your digestive system becomes more active — leading to gas, looser stools, and cramping.

How Long Does Premenstrual Gas Last?

Premenstrual gas typically begins a few days to a week before your period and can continue through the first few days of bleeding.

This pattern matches your hormonal cycle:

  • After ovulation (around day 14): Progesterone rises, slowing digestion.

  • A few days before your period: Progesterone drops, causing increased bowel movement and gas.

  • During your period: Prostaglandins peak, leading to uterine contractions and more intestinal activity.

For most people, these digestive changes subside once hormone levels stabilize — usually within 2–3 days of starting your period.

Gas and Early Pregnancy: How It Differs

Interestingly, gas and bloating can also occur early in pregnancy — but for slightly different reasons.

During pregnancy, progesterone levels remain elevated to support the developing embryo. This hormone relaxes intestinal muscles, slowing digestion and leading to a “lazy gut.”

As Dr. Bartos notes, this slower movement of food through your system can result in:

  • Bloating

  • Constipation

  • Heartburn

  • Burping

  • Morning sickness

High progesterone also causes food to ferment longer in the intestines, creating more gas.

Additionally, prenatal vitamins with iron can worsen constipation and gas by slowing down bowel movement even more.

Why Premenstrual Gas Smells Worse

You may have noticed that farts before your period can smell stronger than usual — and there’s a reason for that.

According to Ana Tuyama, MD, a gastroenterologist based in New York, smelly gas is caused by bacterial fermentation in the colon.

When your gut bacteria digest undigested food, they release sulfur compounds — the same chemicals responsible for the “rotten egg” smell.

During PMS, hormone changes can alter your gut microbiome, increase fermentation, and affect digestion speed — all of which can make gas more noticeable or pungent.

While it might be embarrassing, passing gas is completely normal and healthy. It’s your body’s way of releasing excess air and pressure from the digestive tract.

Diet and Lifestyle Tips to Reduce Premenstrual Gas

While you can’t stop hormonal changes altogether, certain habits can help minimize gas and bloating before your period.

1. Adjust Your Diet Before Your Period

Making simple changes in your food choices can help regulate digestion and reduce symptoms. Try to:

  • Avoid artificial sweeteners ending in “-ol” (like sorbitol or xylitol).

  • Cut back on dairy or high-fat foods if they usually upset your stomach.

  • Limit caffeine, salty snacks, and sugary foods two weeks before your period.

  • Eat whole, unprocessed foods like vegetables, fruits, whole grains, and lean proteins.

Processed foods tend to increase inflammation and water retention, which can make gas and bloating worse.

2. Stay Hydrated

Drinking plenty of water helps your body flush out excess sodium and supports smooth digestion. Aim for at least 8 glasses per day, especially if you’re prone to bloating.

3. Exercise Regularly

Physical activity improves blood circulation, stimulates digestion, and helps prevent constipation.
Try gentle options like walking, yoga, or cycling during PMS and your period — these can reduce cramps and gas buildup.

4. Manage Stress

Stress can worsen gut symptoms by releasing cortisol, which affects digestion.
Use relaxation techniques such as deep breathing, meditation, or warm baths to ease both stress and cramps.

5. Track Your Cycle

Keeping a menstrual diary helps you notice when symptoms begin and end each month.
You can then prepare by adjusting your diet or activity in the days leading up to your period.

When To See a Healthcare Provider

While gas and bloating are normal during PMS, it’s important to talk to a doctor if symptoms are severe or interfere with your daily life.

Seek medical advice if you experience:

  • Persistent abdominal pain or diarrhea

  • Sudden, unexplained weight loss

  • Blood in your stool

  • Severe bloating that doesn’t improve

  • Gas that lasts throughout your entire cycle

Your healthcare provider can help rule out conditions like IBS, lactose intolerance, or endometriosis, which can mimic or worsen premenstrual GI symptoms.

The Bottom Line

Gas before your period is a natural and common PMS symptom caused by fluctuating hormones that affect digestion and gut activity.

Although you can’t completely prevent premenstrual gas, eating clean, staying hydrated, and moving your body regularly can help minimize discomfort.

If your digestive symptoms become unusually painful or persistent, a doctor can help you identify other possible causes and develop a personalized plan for relief.

Remember — it’s totally normal to feel bloated or gassy before your period. Your body is adjusting to powerful hormonal changes each month, and those shifts are a sign of a healthy reproductive system.