What could be causing lower left abdominal pain in a woman?

Left lower quadrant (LLQ) abdominal pain in women can arise from a wide range of causes—some benign and self-limiting, others urgent or life-threatening. The differential diagnosis must account for both gastrointestinal and gynecologic structures located in this region, including the descending colon, sigmoid colon, left ureter, left ovary, left fallopian tube, and adjacent pelvic peritoneum.

Common non-urgent causes include constipation, diverticulosis or uncomplicated diverticulitis (particularly in older adults), irritable bowel syndrome (IBS), and functional abdominal pain. Musculoskeletal strain or nerve irritation (e.g., from the ilioinguinal or genitofemoral nerves) may also present as localized LLQ discomfort.

Gynecologic etiologies require careful evaluation—especially in reproductive-age women. These include ovarian cysts (e.g., hemorrhagic or ruptured cysts), endometriosis involving the left uterosacral ligament or sigmoid colon, salpingitis (often part of pelvic inflammatory disease), ectopic pregnancy (though classically associated with unilateral adnexal tenderness, it may localize to the left side), and ovarian torsion (a surgical emergency characterized by sudden, severe pain, often with nausea and vomiting).

Urologic causes such as left-sided ureteral colic from nephrolithiasis or pyelonephritis should also be considered—particularly if pain radiates to the groin or is accompanied by dysuria, hematuria, or fever. Less common but important diagnoses include inflammatory bowel disease (e.g., Crohn’s disease or ulcerative colitis affecting the sigmoid colon), mesenteric lymphadenitis, or, rarely, malignancy (e.g., sigmoid colon adenocarcinoma or ovarian cancer).

A thorough clinical assessment—including detailed history (onset, character, duration, exacerbating/relieving factors, menstrual and obstetric history, bowel and urinary symptoms), physical examination (with pelvic and rectal components when appropriate), and targeted investigations (e.g., urinalysis, pregnancy test, pelvic ultrasound, CT abdomen/pelvis, or colonoscopy)—is essential to guide diagnosis and management. Any woman presenting with acute, severe, or worsening LLQ pain—especially with fever, vomiting, vaginal bleeding, syncope, or signs of peritoneal irritation—requires prompt evaluation to rule out surgical emergencies.