Lower abdominal pain has dozens of possible causes, ranging from a mild bladder infection to a surgical emergency like appendicitis. About one in five adults who visit an emergency department for abdominal pain leave without a specific diagnosis, which tells you how tricky this symptom can be to pin down. The location, quality, and timing of your pain, along with other symptoms you’re experiencing, are the best clues to narrowing the list.
Digestive Causes
The most common digestive culprits behind lower abdominal pain are appendicitis, diverticulitis, constipation, and irritable bowel syndrome (IBS). Each has a somewhat different pattern.
Appendicitis typically starts as a vague ache around the belly button, then migrates to the lower right side over several hours. The pain gets worse when you move, cough, sneeze, or take deep breaths. You may also lose your appetite, feel nauseous, develop a low fever, or notice you can’t pass gas. This is a time-sensitive emergency: a burst appendix can cause a dangerous infection in your abdominal cavity.
Diverticulitis happens when small pouches in the colon wall become inflamed or infected. It’s classically felt in the lower left side, though in some people (particularly younger adults and those of Asian descent) it can strike the right side and closely mimic appendicitis. The pain tends to be constant rather than crampy, and it often comes with fever and changes in bowel habits.
Constipation is easy to overlook as a cause of real pain, but when stool backs up in the colon it can produce cramping across the entire lower abdomen. IBS follows a similar pattern of cramping and bloating, usually relieved (at least temporarily) by a bowel movement.
Inflammatory Bowel Disease
Crohn’s disease and ulcerative colitis both cause chronic inflammation in the digestive tract, but they affect different areas. Ulcerative colitis is limited to the colon and almost always starts at the rectum, extending upward in a continuous stretch. That means cramps and bleeding are typically centered in the lower abdomen. Crohn’s disease can appear anywhere from the mouth to the anus and often skips areas, leaving patches of healthy tissue between inflamed spots. When it affects the end of the small intestine, which is common, you’ll feel pain in the lower right abdomen.
Both conditions tend to flare and remit over months or years. Bloody diarrhea, urgency, fatigue, and unintended weight loss are hallmarks. If you’ve been dealing with recurring lower abdominal pain paired with changes in your stool for weeks, inflammatory bowel disease is worth investigating.
Urinary Tract Problems
A bladder infection (cystitis) produces pain or pressure in the lower abdomen, right above the pubic bone. The signature symptom is a burning sensation when you urinate, along with the constant feeling that you need to go even when your bladder is nearly empty. Urine may look cloudy or smell unusual.
Kidney stones cause a very different kind of pain. It’s usually sharp and stabbing, starting in the back or side and radiating down toward the lower abdomen and groin as the stone moves through the urinary tract. The pain can come in intense waves, and many people also experience nausea, vomiting, or blood in their urine. If you’re unsure which you’re dealing with, the location is the biggest clue: bladder infection pain stays low and central, while kidney stone pain often starts higher and moves.
Causes Specific to Women
The reproductive organs sit in the lower pelvis, so conditions affecting the uterus, ovaries, or fallopian tubes frequently show up as lower abdominal pain.
Menstrual cramps are the most common cause and need little explanation, but pain that’s severe enough to interfere with daily life or that worsens over time could point to endometriosis. In endometriosis, tissue similar to the uterine lining grows outside the uterus, often on the ovaries, fallopian tubes, or pelvic walls. It can cause deep, aching pain that flares around your period but may also persist throughout the month.
Ovarian cysts are fluid-filled sacs that form on or inside an ovary. Most are harmless and resolve on their own, but a large or ruptured cyst causes sudden, sharp pain on one side of the lower abdomen. A ruptured cyst can also cause internal bleeding, which makes the pain spread and may leave you feeling dizzy or faint.
Ectopic pregnancy is a serious emergency. It occurs when a fertilized egg implants outside the uterus, almost always in a fallopian tube. The first warning signs are light vaginal bleeding and pelvic pain, often on one side. If the tube ruptures, you may feel sudden severe pain, shoulder pain (from blood irritating the diaphragm), extreme lightheadedness, or fainting. A home pregnancy test will be positive. Any combination of a positive pregnancy test with pelvic pain and bleeding warrants immediate medical attention.
Causes Specific to Men
Inguinal hernias are one of the most common causes of lower abdominal and groin pain in men. They occur when a loop of intestine pushes through a weak spot in the abdominal wall near the inguinal canal, the passage where the spermatic cord enters the scrotum. You’ll typically notice a bulge on one side of your pubic bone that becomes more obvious when you stand up, cough, or strain. The area may burn or ache, and large hernias can extend into the scrotum, causing swelling and pain there as well.
Prostatitis, or inflammation of the prostate gland, causes a deep ache between the scrotum and rectum that can radiate into the lower abdomen. It often comes with painful urination, difficulty starting or stopping your stream, and sometimes fever. Testicular torsion, where a testicle twists on its blood supply, causes sudden severe pain in the scrotum that radiates upward into the lower abdomen. It’s most common in teenagers and young men and requires emergency treatment within hours to save the testicle.
How Doctors Figure Out the Cause
Your doctor will start with your symptom history and a physical exam, then decide whether you need blood work, urine tests, or imaging. The type of imaging depends on where the pain is and what’s suspected.
CT scans are the first-choice imaging study for pain in either the lower right or lower left quadrant. For suspected appendicitis, CT picks up the problem about 91% of the time, compared to about 78% for ultrasound. For diverticulitis, CT is even more accurate, with sensitivity above 95%, and it can reveal complications like abscesses. Ultrasound is sometimes used first in younger patients or pregnant women to avoid radiation exposure, with CT reserved for cases where ultrasound results are unclear.
If the diagnosis remains uncertain after imaging, your doctor may order additional tests or refer you to a specialist. Not every episode of lower abdominal pain gets a neat label on the first visit, and a period of watchful waiting is common when initial tests come back normal.
Signs You Need Emergency Care
Most lower abdominal pain resolves on its own or turns out to be something manageable. But certain patterns signal a problem that can’t wait.
- Pain so severe it stops you from functioning, especially if it came on suddenly
- Vomiting you can’t control or an inability to keep liquids down
- Complete inability to pass stool or gas, which could indicate a bowel obstruction
- Fever with worsening abdominal pain, suggesting infection or inflammation
- Signs of internal bleeding such as dizziness, fainting, a rapid pulse, or shoulder pain alongside pelvic pain
- A positive pregnancy test with pelvic pain or vaginal bleeding
If you’ve had previous abdominal surgery, adhesions (scar tissue) can sometimes cause bowel obstructions, so recurring pain after a past operation deserves extra attention. And pain that resembles something you’ve experienced before but feels different this time, more intense, in a new location, or accompanied by new symptoms, is worth getting checked promptly.