Lower stomach pain has a wide range of possible causes, from minor digestive issues to conditions that need prompt treatment. The most common diagnoses for abdominal pain in primary care are gastroenteritis, irritable bowel syndrome, urinary conditions, and inflammation of the stomach lining. Interestingly, a large British study found that roughly 80% of people who visit their doctor for abdominal pain never receive a specific diagnosis, meaning the pain resolves on its own or remains unexplained.
Where exactly you feel the pain, how it started, and what other symptoms come with it all matter. Here’s what the location and character of your pain can tell you.
Why Location Matters
Your lower abdomen contains different organs on each side, so the spot where you feel pain is one of the strongest clues to its cause. The right side holds the appendix, the beginning of the large intestine, and in women, the right ovary and fallopian tube. The left side holds the end of the large intestine (including the sigmoid colon), and the left reproductive organs in women. The center, just above the pubic bone, sits over the bladder, the lowest part of the colon, and in women, the uterus.
Pain that stays in one area typically points toward an organ in that region. Pain that’s harder to pin down, or that shifts around, is more commonly related to the intestines, gas, or a generalized issue like a stomach bug.
Pain on the Right Side
Right-sided lower abdominal pain is most commonly associated with appendicitis. The classic pattern starts as a vague ache around the belly button, then migrates to the lower right over the course of several hours. Walking, coughing, or any movement that puts pressure on the abdomen tends to make it worse. About 75% of people with appendicitis show up for care within 24 hours of their first symptom.
Appendicitis can escalate quickly. The risk of the appendix rupturing starts at around 2% at 36 hours from symptom onset, then climbs roughly 5% for every additional 12 hours without treatment. That’s why new, persistent right-sided pain that gets steadily worse deserves same-day medical attention, not a wait-and-see approach.
Other right-sided causes include ovarian cysts or ovulation pain in women, kidney stones traveling down the right ureter, and occasionally inflammation of the intestine from infections or conditions like Crohn’s disease.
Pain on the Left Side
The left lower abdomen is the most common site for diverticulitis, an infection or inflammation of small pouches that form in the colon wall. It tends to affect people over 50 and often comes with fever and pain that lasts for days rather than hours. Diverticular disease was diagnosed within a year in about 2% of men and 1.5% of women who visited their doctor for abdominal pain in a large primary care study.
Irritable bowel syndrome (IBS) also frequently causes left-sided lower pain, often with bloating, cramping, and changes in bowel habits. Unlike diverticulitis, IBS doesn’t cause fever or blood in the stool. It’s more common in women and tends to be closely linked to stress, diet, and how the brain processes gut signals, rather than visible inflammation in the intestine.
Pain in the Center, Near the Pubic Bone
A dull ache or pressure just above the pubic bone often points to the bladder. Urinary tract infections (UTIs) are the single most common diagnosis in women with abdominal pain, found in about 5% of women within a year of their first visit. Men get UTIs less often, at about 1%. Along with the lower abdominal pressure, you’ll usually notice burning with urination, a frequent urge to go, or cloudy urine.
Constipation is another extremely common cause of central lower pain. When stool builds up in the sigmoid colon and rectum, it can create a crampy, full feeling low in the abdomen that resolves once you have a bowel movement.
Causes That Affect Women Specifically
Several gynecological conditions cause lower abdominal pain that can be confused with digestive problems. Ovarian cysts are fluid-filled sacs on the ovary that often cause no symptoms at all but can produce a sharp, sudden pain if they rupture or twist. Uterine fibroids, noncancerous growths in the uterine wall, were diagnosed in about 1.3% of women seeking care for abdominal pain within a year.
Pelvic inflammatory disease (PID) is an infection of the reproductive organs, usually caused by sexually transmitted bacteria. It produces lower abdominal tenderness, and immediate treatment is important because untreated PID can lead to chronic pelvic pain, ectopic pregnancy, and infertility. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, causes pain that often worsens around menstruation and can be difficult to diagnose without imaging or surgery.
Any lower abdominal pain in a woman of childbearing age also warrants considering pregnancy-related causes, including ectopic pregnancy, which is a medical emergency.
Causes That Affect Men Specifically
Inguinal hernias are 8 to 10 times more common in men than women. They happen when tissue pushes through a weak spot in the abdominal wall near the groin. You might notice a visible bulge that becomes more obvious when you stand up, cough, or strain. Large hernias can extend into the scrotum, causing pain and swelling there as well.
Prostatitis, inflammation of the prostate gland, can cause a deep ache in the lower abdomen or pelvis along with urinary symptoms. Testicular torsion, where a testicle twists on its blood supply, produces sudden severe pain that often radiates into the lower abdomen and requires emergency treatment.
Acute Pain vs. Recurring Pain
Pain that develops over hours to days and then goes away is considered acute. Most episodes of lower abdominal pain fall into this category and are caused by things like gas, a stomach virus, constipation, or a mild infection. Chronic abdominal pain, by contrast, comes and goes over weeks, months, or even years. Conditions like IBS, endometriosis, and inflammatory bowel disease tend to follow this chronic, recurring pattern.
The distinction matters because acute pain that’s getting worse needs evaluation sooner, while chronic pain that you’ve been living with points toward conditions that require a different diagnostic approach, often involving imaging or specialist referral over time rather than an emergency visit.
How Doctors Figure Out the Cause
A careful history and physical exam narrow down the possibilities significantly. If imaging is needed, the approach depends on your sex, age, and what the doctor suspects. For women of childbearing age with possible gynecological causes, ultrasound (either over the abdomen or transvaginal) is the first-line test. When a gastrointestinal or urinary cause seems more likely, a CT scan of the abdomen and pelvis with contrast is the preferred imaging tool and is considered the best overall test for undifferentiated abdominal pain. Blood and urine tests help identify infection, inflammation, or pregnancy.
Signs That Need Immediate Attention
Most lower abdominal pain isn’t dangerous, but certain features signal something more serious. Seek emergency care if you experience:
- Sudden, severe pain that comes on abruptly and is intense from the start
- Pain that wakes you from sleep or steadily worsens over hours
- A rigid, board-like abdomen that’s painful to touch
- Vomiting blood or passing blood from the rectum
- High fever with abdominal pain
- A tender bulge in the abdomen or groin that you can’t push back in
- Severe bloating with an inability to pass gas or have a bowel movement
Pain that seems out of proportion to what you see on the surface, meaning it feels far worse than you’d expect, is also a recognized red flag, particularly in older adults or people with weakened immune systems.