Lower abdominal pain has dozens of possible causes, ranging from a mild muscle strain to conditions that need same-day medical attention. The location, timing, and accompanying symptoms usually point toward a specific category of problem. Here’s what the most common causes look like and how to tell them apart.
Pain on the Right Side
The most concerning cause of right-sided lower abdominal pain is appendicitis. It typically starts as a vague ache around the belly button and then migrates over several hours to the lower right abdomen. Nausea, loss of appetite, and a low-grade fever often follow. The classic tender spot sits about one-third of the way from the hip bone to the belly button. If someone presses on your left lower abdomen and you feel pain on the right side, that’s another hallmark sign. Appendicitis pain tends to worsen steadily rather than come and go, and it usually gets worse with movement, coughing, or walking.
Not all right-sided pain is appendicitis, though. Ovarian cysts can rupture or twist on that side, kidney stones passing through the right ureter produce sharp waves of pain, and even a pulled abdominal muscle can mimic something more serious. The key difference is trajectory: appendicitis pain escalates over 12 to 24 hours and doesn’t let up, while a muscle strain hurts with specific movements and improves with rest.
Pain on the Left Side
Left-sided lower abdominal pain in adults over 50 is often diverticulitis, an infection or inflammation of small pouches that form in the wall of the colon. The pattern is fairly recognizable: steady pain in the lower left abdomen that gets worse when you move, tenderness when that area is pressed, fever, and sometimes a change in bowel habits. Vomiting is notably uncommon with diverticulitis, which helps distinguish it from other abdominal emergencies. A clinical prediction model found that being over 50, having tenderness isolated to the left lower abdomen, and the absence of vomiting were among the strongest predictors of acute diverticulitis.
In younger adults, left-sided pain is more likely related to constipation, gas trapped in the descending colon, or, in women, an ovarian issue on that side.
Pain Across the Entire Lower Abdomen
When pain isn’t clearly on one side, the list of possibilities shifts. Several of the most common causes involve the bladder, bowel, or reproductive organs.
Urinary Tract Infections
UTIs are extremely common, affecting over 8.5 million people worldwide in 2021 alone. A lower UTI (bladder infection) typically causes a dull pressure or ache behind the pubic bone, along with burning during urination, frequent urges to go, and cloudy or strong-smelling urine. The pain is usually constant rather than crampy and doesn’t shift with position.
Irritable Bowel Syndrome
IBS is one of the most frequent explanations for recurring lower abdominal pain that doesn’t have a clear structural cause. The current diagnostic standard requires abdominal pain at least four days per month for two months or longer, with the pain connected to bowel movements, a change in how often you go, or a change in stool consistency. Pain that reliably improves or worsens around the time of a bowel movement is the signature feature. IBS pain can occur anywhere in the lower abdomen and often shifts location.
Inflammatory Bowel Disease
Ulcerative colitis and Crohn’s disease both cause lower abdominal pain, but they look different. Ulcerative colitis affects the colon starting at the rectum, so cramps and bleeding tend to center in the lower abdomen. Bloody diarrhea, urgent rushes to the bathroom, and the feeling that you still need to go even after a bowel movement are characteristic. Crohn’s disease, by contrast, more often involves pain with nonbloody diarrhea and unintended weight loss, particularly when the small intestine is involved. Crohn’s can also cause problems around the anus, including painful fissures and abnormal drainage.
Kidney Stones
Kidney stone pain can mimic lower abdominal conditions because of the way the pain travels. It usually begins in the flank, the area on either side of your mid-back between the pelvis and ribs, then moves around toward the abdomen and groin as the stone shifts. The pain comes from swelling of the kidney as urine backs up behind the stone. Because the kidney isn’t a flexible organ, even mild swelling irritates the nerves on its surface intensely. The result is often described as the worst pain a person has ever felt, arriving in waves and sometimes accompanied by nausea, blood in the urine, or a persistent need to urinate.
Causes More Common in Women
Pelvic inflammatory disease is an infection of the uterus, fallopian tubes, or ovaries, most often caused by sexually transmitted bacteria. It’s tricky to identify because symptoms are frequently subtle or easy to dismiss: mild lower abdominal pain, abnormal bleeding, discomfort during sex, and unusual vaginal discharge. Many women have PID with no obvious symptoms at all. The CDC recommends that any sexually active woman with unexplained pelvic or lower abdominal pain be evaluated for PID, especially when tenderness is found during a pelvic exam. Left untreated, PID can lead to scarring and fertility problems.
Ovarian cysts, ovarian torsion (when an ovary twists on its blood supply), ectopic pregnancy, and menstrual cramps are other female-specific causes. Ectopic pregnancy deserves particular attention: any woman of reproductive age with sudden lower abdominal pain, a missed period, and vaginal bleeding needs immediate evaluation, because a ruptured ectopic pregnancy can cause life-threatening internal bleeding.
Causes More Common in Men
Inguinal hernias are far more common in men and often show up as lower abdominal or groin pain accompanied by a visible or palpable bulge. The bulge may extend into the scrotum. The hallmark pattern is pain and heaviness that worsen when you strain, lift, cough, or stand for extended periods and improve when you rest or lie down. Hernias don’t always require immediate surgery, but a hernia that becomes suddenly painful, firm, and impossible to push back in (called incarceration) is a surgical emergency.
Testicular torsion and prostatitis (infection or inflammation of the prostate) can also produce pain that radiates into the lower abdomen in men, though the primary discomfort is usually felt lower.
What Your Doctor Will Check
A physical exam for lower abdominal pain follows a structured approach. Your doctor will press on specific areas to see where tenderness is worst and whether the pain changes with certain movements. For suspected appendicitis, they’ll check a spot called McBurney’s point on the right side, which has a sensitivity of 50 to 94 percent for confirming the diagnosis. They may also passively extend or rotate your hip to see whether deep pelvic muscles are irritated, which can point to an abscess or inflamed appendix sitting in an unusual position.
Beyond the physical exam, common next steps include blood work to check for infection or inflammation, a urine test to rule out a UTI or kidney stone, and imaging. Ultrasound is typically the first choice for pelvic and reproductive concerns, while a CT scan is better for evaluating the appendix, diverticula, and kidney stones.
Signs That Need Urgent Attention
The American College of Emergency Physicians advises seeking emergency care if abdominal pain is sudden, severe, or doesn’t ease within 30 minutes. Continuous severe pain accompanied by nonstop vomiting is another red flag that may indicate a serious or life-threatening condition. Other warning signs include fever above 101°F, an abdomen that’s rigid or extremely tender to touch, bloody stool or vomit, dizziness or fainting, and inability to pass gas or have a bowel movement (which can signal an obstruction).
Pain that started mild and has steadily worsened over hours, particularly with fever and loss of appetite, follows the classic pattern of appendicitis or another condition that may need surgical evaluation. In that situation, avoiding food and drink while getting to a doctor is the safest approach.