Lower stomach pain has dozens of possible causes, ranging from trapped gas that resolves in hours to conditions that need urgent treatment. The most common culprits fall into a few categories: digestive problems, urinary tract issues, reproductive organ conditions, and muscle or nerve dysfunction in the pelvic floor. Where exactly the pain sits, how long it lasts, and what other symptoms come with it are the biggest clues to what’s going on.
Digestive Causes
Irritable bowel syndrome (IBS) is one of the most frequent reasons for recurring lower abdominal pain. Global estimates put the prevalence around 11 to 13% of the population, and it affects women roughly twice as often as men. IBS pain typically comes in cramping waves, often triggered by eating, and tends to improve after a bowel movement. It can shift between constipation, diarrhea, or both. The pain rarely wakes you from sleep, and it doesn’t come with fever or blood in the stool.
Diverticulitis feels different. Small pouches that form in the colon wall can become inflamed or infected, usually causing steady pain in the lower left side. Unlike IBS, diverticulitis pain often lasts longer than 24 hours and is severe enough to send people to a doctor. Research comparing the two conditions found that pain persisting beyond a full day was far more common in diverticulitis (about 22%) than IBS (roughly 7%), making duration one of the clearest distinguishing features.
Food-related pain is also extremely common. The interaction between your immune system, gut bacteria, and certain food components can trigger lower abdominal cramping after meals. Many people can identify a few foods that consistently bother them, but not all triggers are easy to pinpoint. Bloating and gas from fermentation in the large intestine create pressure that stretches the bowel wall, which your nerves register as pain.
Constipation deserves its own mention. When stool builds up in the colon, it causes a dull, widespread ache across the lower abdomen that can feel surprisingly intense. It’s often accompanied by bloating and a sense of fullness. Gastroenteritis, or a stomach bug, tends to produce cramping pain alongside diarrhea and sometimes vomiting. If diarrhea is your main symptom alongside the pain, an infection is more likely than something structural.
Urinary Tract Infections
A bladder infection can cause pressure or cramping in the lower abdomen or groin that people often mistake for a digestive issue. The key difference is that UTI pain usually comes with urinary symptoms: burning when you pee, needing to go frequently, or feeling like you can’t fully empty your bladder. The lower abdominal pressure from a UTI sits low and central, just above the pubic bone, and it may feel worse when the bladder is full. UTIs are far more common in women, though men can get them too, especially later in life.
Reproductive Causes in Women
For women, the reproductive organs sit right in the lower pelvis, and problems with them frequently present as lower stomach pain. Menstrual cramps are the most obvious example, but several other conditions cause similar or more severe pain.
Ovarian cysts are fluid-filled sacs that form on the ovaries, usually during the menstrual cycle. Most are harmless and disappear on their own. But when a cyst ruptures or bleeds, it can cause sudden, sharp pain on one side of the lower abdomen. In rare severe cases, a ruptured cyst can cause enough internal bleeding to drop blood pressure, making it a medical emergency. Ovarian torsion, where the ovary twists on its blood supply, causes intense one-sided pain along with nausea and vomiting. This requires immediate treatment.
Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus. It typically causes chronic, cyclic pelvic pain that worsens around menstruation, though it can also flare acutely if an endometriotic cyst ruptures or becomes infected. Pelvic inflammatory disease (PID), usually caused by sexually transmitted bacteria, produces a wide range of symptoms from mild lower abdominal discomfort to fever, unusual vaginal discharge, and pain during sex.
Ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), can cause lower abdominal pain that starts mild and becomes severe if the tube ruptures. This typically happens around 10 to 14 weeks and can involve heavy internal bleeding. Any sudden lower abdominal pain with vaginal bleeding in a woman of childbearing age warrants immediate evaluation.
Causes More Common in Men
Prostatitis, or inflammation of the prostate gland, causes pain in the lower belly, groin, or lower back. It can also produce discomfort in the area between the scrotum and rectum, painful urination, and pain during ejaculation. Prostatitis can be bacterial (and treatable with antibiotics) or non-bacterial (chronic pelvic pain syndrome), which is harder to manage and more common.
Inguinal hernias, where tissue pushes through a weak spot in the abdominal wall near the groin, are far more common in men. The pain usually gets worse with coughing, bending, or lifting. You may notice a visible bulge in the groin area that becomes more obvious when standing or straining.
Pelvic Floor Dysfunction
Your pelvic floor is a group of muscles that stretches across the bottom of your pelvis, supporting your bladder, bowel, and (in women) uterus. When these muscles can’t properly relax and contract, the result is ongoing pain in the pelvic region that can feel like lower stomach pain. People with pelvic floor dysfunction often struggle with bowel movements, feeling like they can’t fully empty, or they may have to strain excessively. Frequent stopping and starting during urination, painful urination, and leakage of urine or stool are other hallmarks.
Pelvic floor dysfunction can develop after childbirth, surgery, chronic straining from constipation, or even prolonged stress. It overlaps with and can worsen bladder conditions that cause persistent pelvic pain. Physical therapy focused on retraining pelvic floor muscles is the primary treatment, and it works well for many people.
Appendicitis: How to Spot It
Appendicitis deserves special attention because it starts as vague stomach discomfort and then changes in a recognizable way. In the early stages, the pain sits around the middle of the abdomen and feels like a general upset stomach. Over several hours to a couple of days, it migrates to the lower right side and becomes sharper and more localized. Nausea and vomiting often accompany it, but diarrhea points more toward a stomach bug than appendicitis.
The pain tends to worsen with movement, coughing, or pressing on the area. If your appendix tears, the pain may initially feel like it improves before spreading across the entire abdomen as infection sets in. This is a surgical emergency.
How Doctors Figure Out the Cause
Because so many conditions share overlapping symptoms, diagnosis relies on combining your description of the pain with physical examination, lab work, and imaging. Ultrasound is typically the first imaging tool, especially for suspected reproductive or urinary causes. It’s quick, noninvasive, and effective at detecting cysts, ectopic pregnancies, and fluid collections. If ultrasound doesn’t give a clear answer, or if a digestive or urinary cause is more likely, a CT scan with contrast is the preferred next step. CT scans are particularly good at identifying appendicitis, diverticulitis, and kidney stones.
Urine tests can quickly confirm or rule out a UTI or pregnancy. Blood work showing elevated white blood cells or inflammatory markers helps distinguish infectious or inflammatory causes from functional ones like IBS.
Patterns That Help You Narrow It Down
Pain that comes and goes with meals and improves after a bowel movement leans toward IBS or food intolerance. Steady pain lasting more than 24 hours with fever suggests something inflammatory like diverticulitis or PID. Sharp, sudden pain on one side in a woman points toward an ovarian cyst rupture or torsion. Pain that started in the center and moved to the lower right over hours is the classic appendicitis pattern. Lower abdominal pressure paired with burning urination is most likely a UTI.
Sudden, severe pain that comes on without warning is the one pattern that always warrants emergency evaluation, regardless of other symptoms. This applies to pain accompanied by fainting, heavy bleeding, high fever, or a rigid abdomen that hurts when you press on it and then release.