Lower abdominal pain has dozens of possible causes, ranging from temporary digestive issues like gas and constipation to conditions that need medical attention, like appendicitis or kidney stones. Where exactly you feel the pain, what kind of pain it is, and what other symptoms you have all help narrow down what’s going on. Here’s a breakdown of the most common reasons.
Digestive Causes
The most frequent culprits behind lower abdominal pain are gastrointestinal. Constipation alone accounts for a huge share of cases, producing crampy, pressure-like discomfort that usually sits in the lower left side, where the last section of your colon is. Gas buildup and bloating can cause sharp, moving pains that shift around and then resolve once you pass gas or have a bowel movement.
Diverticulitis is the most common cause of acute pain specifically in the lower left abdomen in adults. It happens when small pouches that form in the colon wall (most often on the left side) trap bacteria and become infected. The classic pattern is left-sided pain with fever and sometimes nausea. It typically requires antibiotics and occasionally hospitalization.
Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, causes chronic or recurring pain along with diarrhea, bloody stools, and fatigue. Irritable bowel syndrome produces similar cramping and changes in bowel habits but without the visible inflammation. Both tend to flare and then improve in cycles.
Infectious colitis from food poisoning or a stomach bug can also hit the lower abdomen hard, usually alongside diarrhea, cramping, and sometimes fever. These episodes are typically short-lived but can be intense.
Where the Pain Is Matters
Pain in the lower right is the classic location for appendicitis. It often starts as a vague ache around the belly button and then migrates to the right side over several hours, becoming sharper and more localized. Pain in the lower left points more toward diverticulitis or constipation. Pain that sits low and central, just above the pubic bone, often involves the bladder or, in women, the uterus.
Pain that radiates from your back or side and wraps around to the front is a hallmark of kidney stones. Stones produce intense, wave-like pain as they move through the narrow tubes connecting your kidneys to your bladder. You may also notice blood in your urine, nausea, or a frequent urge to urinate.
Reproductive and Pelvic Causes in Women
Several conditions unique to the female reproductive system cause lower abdominal pain. Ovarian cysts, which are fluid-filled sacs on or in the ovaries, are extremely common and usually painless. But when a cyst ruptures or grows large enough to twist the ovary (ovarian torsion), the pain can be sudden and severe, usually on one side.
Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus, attaching to organs in the pelvis. It causes pain that often worsens during periods but can persist throughout the month. Pelvic inflammatory disease, an infection of the reproductive organs usually linked to sexually transmitted bacteria, produces lower abdominal pain along with unusual discharge, pain during sex, and sometimes fever.
Menstrual cramps themselves are a leading cause of cyclical lower abdominal pain. Mittelschmerz, a brief, one-sided pain that happens around ovulation (mid-cycle), is another normal cause that can feel alarming if you’re not expecting it. In early pregnancy, lower abdominal pain paired with vaginal bleeding can signal an ectopic pregnancy or miscarriage, both of which need urgent evaluation.
Urinary Tract Problems
A urinary tract infection typically causes a burning sensation when you urinate, a constant feeling that you need to go, and a dull ache or pressure in your lower abdomen just above the pubic bone. UTIs are far more common in women but can affect anyone. Kidney stones produce more dramatic symptoms: serious pain that comes in waves, nausea, vomiting, fever, chills, and sometimes visible blood in the urine. The pain often starts in the flank and moves downward as the stone travels.
Hernias and Muscle Strain
Not all lower abdominal pain comes from internal organs. An inguinal hernia, where part of the intestine pushes through a weak spot in the abdominal wall near the groin, causes a burning or aching sensation and sometimes a visible bulge. The pain gets worse when you cough, bend over, or lift something heavy. In men, the hernia can descend into the scrotum, causing swelling and pain around the testicles.
A hernia that becomes trapped (incarcerated) or loses its blood supply (strangulated) is a surgical emergency. Warning signs include sudden worsening pain, nausea and vomiting, inability to pass gas or have a bowel movement, and a bulge that turns red or purple.
Abdominal muscle strains from exercise, heavy lifting, or even prolonged coughing can also mimic deeper pain. The key difference: muscle pain typically worsens when you tense your abs (like doing a sit-up) and feels sore to the touch on the surface, rather than deep inside.
Prostate-Related Pain in Men
Prostatitis, inflammation or infection of the prostate gland, can cause a deep ache in the lower abdomen, groin, or perineum (the area between the scrotum and rectum). It sometimes comes with painful urination, difficulty urinating, or pain during ejaculation. Acute bacterial prostatitis tends to come on suddenly with fever, while chronic prostatitis develops more gradually and can linger for months.
What the Type of Pain Tells You
Crampy pain that comes and goes in waves usually points to something in the digestive or urinary tract, like gas, constipation, or a kidney stone passing through. Steady, constant pain that gradually worsens is more typical of inflammation or infection, such as appendicitis or diverticulitis. Sharp, sudden-onset pain that takes your breath away suggests something has ruptured or twisted, like an ovarian cyst or ovarian torsion.
Dull, achy pain that you’ve had on and off for weeks or months is more consistent with chronic conditions like endometriosis, IBS, or inflammatory bowel disease. Pain that you can pinpoint with one finger tends to involve the abdominal wall (a hernia or muscle strain), while pain that’s hard to localize usually originates from an internal organ.
Signs That Need Urgent Attention
Most lower abdominal pain resolves on its own or with simple treatment. But certain combinations of symptoms signal something more serious. Seek emergency care if you have severe abdominal pain along with a rigid or distended abdomen, high fever, or pain so intense you can’t stand up straight. Vomiting blood, passing black or bloody stools, or being completely unable to pass gas or have a bowel movement are also red flags.
Pain in the lower right that steadily worsens over 12 to 24 hours, especially with loss of appetite and nausea, warrants evaluation for appendicitis. In women of reproductive age, sudden one-sided pain with dizziness or fainting could indicate a ruptured ectopic pregnancy or a hemorrhaging ovarian cyst, both of which can cause dangerous internal bleeding.
How Doctors Figure Out the Cause
Diagnosis usually starts with a physical exam and questions about when the pain started, where exactly it is, and what makes it better or worse. Blood and urine tests can check for infection, inflammation, and pregnancy. For women of reproductive age, a pregnancy test is standard whenever lower abdominal pain is being evaluated.
CT scans are the go-to imaging study for both right and left lower abdominal pain when a doctor suspects something like appendicitis or diverticulitis. For women with suspected gynecologic causes, pelvic ultrasound (transvaginal or transabdominal) is typically the first imaging step. Pregnant patients are generally evaluated with ultrasound or MRI to avoid radiation exposure. CT is reserved for situations where those options are unavailable or inconclusive and there’s real concern about a serious diagnosis.