Lower stomach pain in women typically comes from one of three systems packed into the lower abdomen: the digestive tract, the reproductive organs, or the urinary tract. Most of the time, the cause is something common and treatable, like gas, constipation, menstrual cramps, or a urinary tract infection. But because so many organs share that small space, pinpointing the source matters.
Digestive Causes Are the Most Common
Your small and large intestines take up most of the room in your lower abdomen, which makes digestive problems the single most frequent reason for pain in that area. Everyday issues like gas, bloating, indigestion, constipation, and diarrhea can all produce cramping or pressure that centers below your belly button. This kind of pain often comes and goes with meals or bowel movements, and you may notice it gets better after passing gas or using the bathroom.
More persistent digestive pain can signal something beyond a bad meal. Irritable bowel syndrome (IBS) causes recurring cramping, bloating, and changes in bowel habits that tend to flare with stress or certain foods. Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, involves chronic inflammation in the intestines and often brings bloody stool, weight loss, or fatigue alongside pain. Celiac disease, food intolerances, and infections can also inflame the intestinal lining and produce ongoing lower abdominal discomfort.
One useful clue: if your pain clearly tracks with your digestive cycle (worse after eating, relieved by a bowel movement, accompanied by changes in stool), the gut is the most likely source.
Reproductive Causes Unique to Women
Menstrual Cramps and Ovulation Pain
Period cramps are the most obvious reproductive cause. The uterus contracts to shed its lining, producing a dull, throbbing ache in the lower center of your abdomen that often radiates into the lower back and thighs. This is normal and predictable, starting just before or at the beginning of your period and lasting one to three days.
Ovulation pain, sometimes called mittelschmerz, is a brief, one-sided twinge or ache that happens midcycle, typically between days 7 and 24. It occurs on whichever side released an egg that month. The pain usually resolves within 3 to 12 hours and is completely harmless, though it can catch you off guard if you’ve never noticed it before.
Ovarian Cysts
Fluid-filled sacs form on the ovaries regularly during the menstrual cycle, and most dissolve on their own without symptoms. When a cyst grows large enough to stretch the ovary or ruptures, it can cause a sudden, sharp pain on one side of your lower abdomen. A ruptured cyst sometimes brings a wave of intense pain that gradually fades over hours. Large or persistent cysts may produce a feeling of fullness, bloating, or a dull ache that lingers for days.
Endometriosis
Endometriosis causes tissue similar to the uterine lining to grow outside the uterus, often on the ovaries, fallopian tubes, or pelvic walls. The hallmark is pelvic pain that goes well beyond typical period cramps. It often starts before your period begins, persists throughout, and doesn’t respond well to standard pain relievers or birth control pills. Many women with endometriosis also experience pain during sex, pain with bowel movements, and pain while urinating. Research has shown that women with endometriosis have greater sensitivity to internal organ pain than even those with IBS, which helps explain why the discomfort can feel so disproportionate.
Endometriosis takes an average of several years to diagnose because its symptoms overlap with so many other conditions. There is no blood test for it. The definitive diagnosis requires a minor surgical procedure called laparoscopy, where a camera is inserted through a small incision near the belly button to visually inspect the pelvis.
Pelvic Inflammatory Disease
Pelvic inflammatory disease (PID) is an infection of the uterus, fallopian tubes, or ovaries. It is most often caused by sexually transmitted infections like chlamydia or gonorrhea, though other bacteria can trigger it too. PID typically produces a constant, deep ache in the lower abdomen, sometimes with unusual vaginal discharge, bleeding between periods, pain during sex, or fever. There is no single test for PID. Diagnosis relies on your symptoms, medical history, and a physical exam, sometimes combined with lab work to check for infection.
Ectopic Pregnancy
An ectopic pregnancy occurs when a fertilized egg implants outside the uterus, most often in a fallopian tube. It is typically diagnosed between weeks 6 and 10 of pregnancy. The pain usually starts on one side of the lower abdomen and can range from mild and persistent to sudden and severe, especially if the tube ruptures. Vaginal bleeding often accompanies the pain. A ruptured ectopic pregnancy is a medical emergency that causes significant abdominal pain, tenderness, and sometimes dizziness or fainting from internal bleeding. If there is any chance you could be pregnant and you have one-sided lower abdominal pain with bleeding, seek emergency care immediately.
Urinary Tract Issues
When the pain sits low and central, right above the pubic bone, and comes with a burning sensation during urination, frequent trips to the bathroom, or strong-smelling or cloudy urine, a urinary tract infection is a likely culprit. UTIs are extremely common in women and produce a recognizable cluster of symptoms: urgency, burning, passing only small amounts of urine, and sometimes blood-tinged or pink urine alongside pelvic pressure.
A kidney infection can also cause lower abdominal pain, though it more commonly starts as back or flank pain and radiates forward. It often brings fever, chills, and nausea on top of the urinary symptoms. Bladder inflammation from other causes (irritants, interstitial cystitis) can mimic a UTI without an actual infection being present.
What the Location of Pain Can Tell You
Where exactly the pain sits offers a useful starting clue. Pain concentrated on the right side could involve the appendix, the right ovary, or the section of large intestine that sits in the lower right abdomen. Left-sided pain more commonly involves the left ovary or diverticulitis, a condition where small pouches in the colon wall become inflamed. Center pain, especially just above the pubic bone, tends to point toward the bladder or uterus. Pain that starts in the back and wraps forward may involve the kidneys.
These are rough guides, not rules. Intestinal pain can show up anywhere in the lower abdomen, and pain from one organ can radiate to unexpected spots. The combination of location, timing, and accompanying symptoms matters more than location alone.
How the Cause Gets Identified
If your pain doesn’t resolve on its own or keeps returning, a healthcare provider will typically start with a detailed history (when the pain started, what it feels like, what makes it better or worse, and how it relates to your menstrual cycle or digestive patterns) and a physical exam of the abdomen and pelvis.
From there, common next steps include:
- Urine test to check for a UTI or pregnancy
- Blood work to look for signs of infection or inflammation
- Pelvic ultrasound to visualize the uterus, ovaries, and surrounding structures using sound waves
- Pelvic MRI for a more detailed look when the ultrasound isn’t conclusive
- Laparoscopy for conditions like endometriosis that can only be confirmed visually
- Colonoscopy or cystoscopy if digestive or bladder conditions need direct inspection
Signs That Need Urgent Attention
Most lower abdominal pain resolves on its own or responds to straightforward treatment. But certain patterns warrant prompt medical attention: sudden, severe pain that won’t let up, pain accompanied by fever or chills, blood in your urine or stool, dizziness or fainting, or any chance you could be pregnant combined with one-sided pain and vaginal bleeding. These combinations can indicate a ruptured cyst, ectopic pregnancy, appendicitis, or a serious infection, all of which benefit from fast evaluation.