Lower abdominal pain is the single most common reason people visit the emergency department in the United States, holding that ranking every year from 2016 through 2022. Most of the time, it comes from something routine like gas, constipation, or a mild stomach bug. But because so many organs are packed into that small space, the same symptom can also signal something that needs prompt attention.
Understanding where the pain is, how it started, and what it feels like can help you narrow down what’s going on.
Why Location Matters
Your lower abdomen is mostly occupied by your small and large intestines, which is why digestive problems are the most frequent cause of pain in this area. But several other organs live there too, and the side that hurts can point toward different issues.
Your right lower abdomen houses your appendix, your right ureter (the tube connecting your kidney to your bladder), and, in women, the right ovary and fallopian tube. Your left lower abdomen contains the corresponding left ureter and left reproductive organs, plus the section of your colon most prone to a condition called diverticulitis. Pain that stays on one side often narrows the list of likely causes considerably.
Common Digestive Causes
Because the intestines take up most of the space in your lower abdomen, digestive issues account for the majority of pain there. The most everyday culprits are gas and bloating, indigestion, constipation, and diarrhea. These tend to cause cramping that comes and goes, often improves after a bowel movement, and resolves within hours to a couple of days.
More persistent digestive conditions can also settle in the lower abdomen:
- Irritable bowel syndrome (IBS) causes recurring cramping, bloating, and changes in bowel habits without visible damage to the intestines. Pain often worsens after eating and eases after using the bathroom.
- Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, involves chronic inflammation that can cause persistent pain, bloody stools, and weight loss over time.
- Diverticulitis happens when small pouches in the colon wall become inflamed or infected. It typically causes steady pain in the lower left abdomen, often with fever and changes in bowel habits. It’s more common after age 40.
- Celiac disease triggers an immune reaction to gluten that damages the small intestine lining, producing lower abdominal cramping, bloating, and diarrhea.
A bowel obstruction, where something physically blocks the intestine, causes intense cramping that builds and fades in waves, along with vomiting and an inability to pass gas or stool. This is a medical emergency.
Urinary Tract Problems
A bladder infection is one of the most overlooked causes of lower abdominal discomfort. It produces a dull pressure or aching feeling low and center in the abdomen, usually paired with burning during urination, a frequent urge to go, and sometimes cloudy or strong-smelling urine. Kidney stones passing through the ureter can cause sharp, intense pain that radiates from the back down into the lower abdomen and groin, often in waves.
Worth noting: about 16% of people with a confirmed kidney stone don’t have any blood in their urine, so the absence of that classic sign doesn’t rule it out.
Causes Specific to Women
The uterus, ovaries, and fallopian tubes all sit in the lower abdomen, so gynecological conditions are a major source of pain in this area for women.
Menstrual cramps are the most common cause and typically produce a familiar, dull aching that starts just before or during a period and fades within a few days. When that kind of pain becomes severe or disabling, endometriosis may be responsible. In endometriosis, tissue similar to the uterine lining grows outside the uterus, responding to hormonal shifts each cycle by bleeding into the abdominal cavity and causing inflammation. The pain is characteristically cyclical: it builds before menstruation, lasts throughout a period, and then eases.
Ovarian cysts are fluid-filled sacs that often form and dissolve without symptoms. When a cyst twists, bleeds internally, or ruptures, it causes sudden, sharp pain on one side. This pain is typically not tied to the menstrual cycle and can appear out of nowhere, sometimes on a background of milder chronic discomfort.
Pelvic inflammatory disease (PID) is an infection of the upper reproductive tract, most common in sexually active women between ages 15 and 24. It causes deep, steady lower abdominal pain, often with unusual discharge, fever, and pain during intercourse. Left untreated, it can lead to abscess formation and long-term fertility problems.
An ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), affects roughly 1 in 90 pregnancies. It causes one-sided lower abdominal pain that can become severe if the tube ruptures. Any sudden lower abdominal pain with a missed period or positive pregnancy test warrants immediate evaluation.
Causes Specific to Men
Men can experience lower abdominal pain from inguinal hernias, where tissue pushes through a weak spot in the abdominal wall near the groin. This typically causes a dull ache that worsens with lifting, coughing, or straining, and you may notice a visible bulge. Prostatitis, or inflammation of the prostate gland, produces a deep ache between the navel and the groin, sometimes with difficulty urinating or pain during ejaculation. Testicular torsion, where the blood supply to a testicle gets twisted, causes sudden severe pain in the scrotum that often radiates up into the lower abdomen. It’s a surgical emergency.
Appendicitis: The Classic Emergency
Appendicitis deserves special attention because it’s common, it can become dangerous quickly, and its pattern is distinctive. The pain usually starts vague and diffuse around the belly button, then migrates over several hours to the lower right abdomen, where it becomes sharper and more constant. It tends to get worse when you move, cough, or press on the area.
A key warning pattern: abdominal pain that is gradually getting worse, doesn’t go away, and settles into the lower right side. Appendicitis can progress to a ruptured appendix, which can cause life-threatening infection.
Acute Pain vs. Chronic Pain
Timing tells you a lot. Acute lower abdominal pain develops over hours to a few days and needs prompt evaluation to rule out problems requiring surgery or urgent treatment, like appendicitis, an ectopic pregnancy, or a bowel obstruction. The priority with acute pain is figuring out whether something needs to be fixed now.
Chronic abdominal pain has been present for months to years. For most people it comes and goes without necessarily getting worse over time. Conditions like IBS, endometriosis, and IBD fall into this category. Chronic pain still deserves a diagnosis, but the urgency is different. The goal shifts from ruling out emergencies to identifying the underlying condition so it can be managed.
How Doctors Figure Out the Cause
When you go in for lower abdominal pain, the evaluation usually starts with blood and urine tests. For women of reproductive age, a pregnancy test is standard. Beyond that, doctors look at markers of infection and inflammation, kidney function, and sometimes markers that point toward specific conditions like pancreatitis.
Imaging is the next step when the cause isn’t obvious. For lower abdominal pain in nonpregnant adults, a CT scan with contrast is the most common choice because it gives a detailed view of the intestines, appendix, and surrounding structures. Ultrasound is preferred as a first step for pregnant patients and is also useful for identifying ovarian cysts, kidney stones, and appendicitis. If ultrasound results are unclear during pregnancy, MRI is preferred over CT to avoid radiation exposure.
Signs That Need Immediate Attention
Most lower abdominal pain resolves on its own or turns out to be something manageable. But certain combinations of symptoms signal a potential emergency:
- Severe pain that came on suddenly and is getting worse
- Pain with a high fever
- Pain with confusion, blotchy skin, or difficulty breathing (possible signs of sepsis)
- Pain that migrates to the lower right side over several hours
- Lower abdominal pain with a positive pregnancy test or missed period
- Inability to pass gas or have a bowel movement along with vomiting
- Pain with bloody stools or vomiting blood
Pain that’s mild but gradually worsening over days, or pain that keeps returning over weeks, also warrants a medical visit even if it doesn’t feel like an emergency. Persistent or worsening patterns are how your body signals that something needs investigation, not just time.