Severe Stomach Pain and Endometriosis: What You Need to Know

Severe stomach pain that comes and goes with your period isn’t just bad luck-it could be endometriosis. Many women assume their cramps are normal, or blame it on food poisoning or stress. But if your pain is so bad you can’t stand up, throw up, or go to work, and it keeps coming back every month, you’re not imagining it. Endometriosis doesn’t just affect the uterus. It can grow on the bowel, bladder, and even the lining of your stomach, causing pain that feels like it’s coming from your gut.

Why endometriosis mimics digestive problems

Endometriosis happens when tissue similar to the lining of the uterus grows outside the womb. These implants bleed and swell during your cycle, just like the uterine lining. But when they land on the intestines, colon, or stomach, your body treats them like invaders. That triggers inflammation, scar tissue, and nerve irritation-all of which cause sharp, cramping, or burning pain in the abdomen.

That’s why so many people with endometriosis go to the doctor thinking they have IBS, Crohn’s, or a stomach bug. They get tested for food allergies, take antacids, or get prescribed laxatives. Nothing helps. The real problem? The tissue growing on their bowel isn’t being seen. A 2023 study in Human Reproduction found that nearly 40% of women with severe abdominal pain and endometriosis were misdiagnosed with gastrointestinal disorders first.

Signs your stomach pain might be endometriosis

Not all stomach pain is endometriosis. But if you notice these patterns, it’s worth asking your doctor:

• Pain that spikes right before or during your period and fades after
• Bloating so bad you look 6 months pregnant, especially around your cycle
• Diarrhea, constipation, or painful bowel movements that match your menstrual timing
• Nausea or vomiting during your period that doesn’t happen at other times
• Pain during or after sex that feels deep in your pelvis or lower belly

These aren’t random symptoms. They’re signals. Endometriosis implants on the bowel can cause the muscle walls to stiffen, making it hard to pass stool. When they grow near nerves in the lower abdomen, they send pain signals that your brain interprets as coming from your stomach. It’s not a coincidence-it’s anatomy.

Where the pain actually comes from

Think of your pelvis as a crowded room. The uterus sits in the middle. Around it are the bladder, rectum, sigmoid colon, and parts of the small intestine. Endometriosis doesn’t care about boundaries. It can attach to any surface it finds. When it grows on the rectosigmoid colon (the last part of the large intestine), it can cause pain during bowel movements. When it wraps around the stomach’s outer lining, it can trigger nausea and early fullness after eating.

Some women report a feeling like something is “pulling” inside their lower belly. Others say it feels like a knife stabbing them when they move or breathe deeply. That’s not gas. That’s endometrial tissue pulling on nerves or sticking organs together with scar tissue. In advanced cases, the bowel can become partially blocked, leading to vomiting and severe constipation.

Why diagnosis takes years

The average time to diagnose endometriosis is 7 to 10 years. Why? Because doctors still think of it as a “period pain” issue, not a systemic disease. Ultrasounds often miss it. Blood tests don’t detect it. The only way to confirm it is through laparoscopic surgery-where a camera is inserted to see the lesions.

Many women are told to take birth control, “just live with it,” or see a gastroenterologist. But if your pain follows your cycle, no GI treatment will fix it. You need a specialist who knows endometriosis can hide in plain sight-inside your abdomen, not just your uterus.

What to do if you suspect endometriosis

If you’ve had severe stomach pain for months or years, especially if it lines up with your period, here’s what to do:

1. Track your symptoms for at least two cycles. Note the day, intensity, and what you were doing when the pain hit.
2. Bring your symptom log to a gynecologist who specializes in endometriosis-not just any OB-GYN.
3. Ask for a pelvic ultrasound, but know it won’t show everything. Deep infiltrating endometriosis often needs an MRI.
4. Request a referral to a surgeon trained in excision surgery. This is the gold standard for removing endometriosis tissue completely.
5. Don’t accept pain as normal. If your doctor says, “It’s just cramps,” get a second opinion.

There’s no cure for endometriosis, but it can be managed. Excision surgery removes the tissue, and many women see their stomach pain drop by 70% or more afterward. Hormone treatments can help slow growth, but they don’t remove existing lesions.

What doesn’t work-and what does

Many people try diet changes, probiotics, or elimination diets hoping to fix endometriosis pain. These can help with bloating or IBS-like symptoms, but they won’t touch the root cause. If the tissue is growing on your bowel, no amount of gluten-free eating will make it disappear.

What does help? Surgery to remove the lesions. Physical therapy for pelvic floor tension. And support groups-because no one should feel alone while suffering in silence.

One patient from Halifax, 32, had been told she had IBS for five years. Her pain was so bad she skipped family dinners. After a pelvic MRI and laparoscopy, surgeons found endometriosis on her sigmoid colon and bladder. After excision surgery, her stomach pain vanished. She didn’t need to change her diet. She just needed the right diagnosis.

When to seek help right away

Severe stomach pain with endometriosis is usually cyclical. But if you experience:

• Sudden, sharp pain that doesn’t match your cycle
• Fever, chills, or vomiting with abdominal pain
• Inability to pass stool or gas for more than 48 hours
• Blood in stool or vomit

-go to the emergency room. These could be signs of bowel obstruction or rupture, which are rare but serious complications.

Living with it-without letting it control you

Endometriosis doesn’t have to define your life. But it does require you to become your own advocate. Keep records. Find a specialist. Ask for imaging. Push for answers. You’re not overreacting. Your pain is real, and it’s treatable.

There are support networks in Halifax and across Canada. Organizations like Endometriosis Canada offer free resources, doctor directories, and peer mentoring. You don’t have to figure this out alone.