How should I evaluate and manage a reproductive‑age woman presenting with lower abdominal pain and pelvic pressure?

Evaluation and Management of Lower Abdominal Pain with Pelvic Pressure in Reproductive-Age Women

Begin with immediate serum or urine β-hCG testing, followed by combined transvaginal and transabdominal ultrasound with Doppler as first-line imaging for all suspected gynecological causes; reserve CT abdomen and pelvis with IV contrast for non-gynecological etiologies or when ultrasound is inconclusive. 1, 2

Initial Diagnostic Algorithm

Step 1: Obtain β-hCG Immediately

• Serum or urine β-hCG must be obtained first in all reproductive-age women to distinguish pregnancy-related from non-pregnancy causes 2
• A positive β-hCG indicates potential ectopic pregnancy, early intrauterine pregnancy complications, or persistent trophoblastic tissue 2
• A negative β-hCG effectively rules out pregnancy complications and shifts focus to gynecological or non-gynecological pathology 2

Step 2: Assess for Emergency Red Flags

• Check vital signs immediately for hemodynamic instability (tachycardia, hypotension) 3
• Evaluate for peritoneal signs: guarding, rigidity, rebound tenderness 3
• Assess for fever, vaginal bleeding, or signs of sepsis 2

Imaging Strategy Based on β-hCG Status

If β-hCG is Positive (Suspected Gynecological Etiology)

Perform combined transvaginal AND transabdominal ultrasound with Doppler imaging as complementary procedures 1

• This combination provides comprehensive evaluation for:

  • Intrauterine pregnancy location and viability 2
  • Ectopic pregnancy (adnexal mass without IUP has positive likelihood ratio of 111) 2
  • Ovarian torsion (enlarged ovary with decreased/absent Doppler flow) 2
  • Tubo-ovarian abscess (93% sensitivity, 98% specificity) 1, 2

• Key ultrasound findings:

  • Endometrial thickness <8mm virtually excludes normal intrauterine pregnancy 2
  • Endometrial thickness ≥25mm virtually excludes ectopic pregnancy 2
  • Incomplete septa, wall thickness >5mm, cogwheel sign, and cul-de-sac fluid suggest pelvic inflammatory disease 1

• CT should NOT be used routinely when β-hCG is positive due to radiation exposure 2

• CT with IV contrast is reserved only for life-threatening situations requiring urgent intervention when ultrasound is inconclusive 1, 2

If β-hCG is Negative (Suspected Gynecological Etiology)

Perform combined transvaginal and transabdominal ultrasound with Doppler as first-line imaging 1

• Ultrasound demonstrates excellent diagnostic accuracy for:

  • Ovarian cysts, hemorrhagic cysts, or ruptured cysts 1
  • Tubo-ovarian abscess (93% sensitivity, 98% specificity) 1, 2
  • Deep pelvic endometriosis (98% sensitivity for rectosigmoid sites, 95% for retrocervical sites) 1, 2
  • Ovarian torsion 2

• Specific ultrasound findings for pelvic inflammatory disease:

  • Thick wall and cogwheel sign present in 100% and 86% of acute cases 1
  • Incomplete septum of tubal wall present in 92% of tubal inflammatory disease 1
  • Pyosalpinx and loculated echogenic fluid in cul-de-sac 1

If β-hCG is Negative (Suspected Non-Gynecological Etiology)

Perform CT abdomen and pelvis with IV contrast as the preferred initial study 1, 4

• Contrast-enhanced CT demonstrates 89% sensitivity and 88% overall accuracy for urgent abdominopelvic diagnoses 4

• CT pelvis alone is inadequate and must always be combined with abdominal imaging 1, 4

• IV contrast is essential for identifying inflammatory processes, vascular abnormalities, and distinguishing solid from cystic structures 4

• Specific indications for CT (β-hCG negative):

  • Ultrasound findings are inconclusive or nondiagnostic 2, 4
  • High clinical suspicion for appendicitis, bowel obstruction, internal hernia, or abscess 2, 4
  • Life-threatening conditions requiring rapid diagnosis 2
  • Severe pain persisting or worsening despite negative initial workup 2

• CT diagnostic performance for common causes:

  • Appendicitis: 92% sensitivity, 99% specificity 1
  • Urinary calculi: 97.2% sensitivity, 99% specificity with color Doppler twinkle artifact 1
  • Internal hernias, bowel obstruction, diverticulitis require contrast for accurate diagnosis 4

If β-hCG Status is Uncertain or Borderline

MRI abdomen and pelvis without IV contrast is preferred over CT 2

• MRI offers excellent soft-tissue detail without ionizing radiation 2
• MRI shows 100% sensitivity and 93.6% specificity for appendicitis in pregnancy 2
• Gadolinium contrast should be avoided in pregnancy unless absolutely necessary (category C) 2

Management Based on Diagnosis

Pelvic Inflammatory Disease (PID)

Initiate empiric broad-spectrum antibiotics immediately when minimum criteria are met (uterine + adnexal + cervical motion tenderness), even before culture results 2

• Coverage must include: N. gonorrhoeae, C. trachomatis, gram-negative facultative bacteria, anaerobes, streptococci 2
• Obtain cervical cultures for gonorrhea/chlamydia to guide partner treatment, but do not delay antibiotics 2
• Do not require multiple criteria before treating—requiring two or more findings reduces sensitivity and misses cases causing permanent reproductive damage 2

Ovarian Torsion

• Urgent surgical consultation is required if ultrasound shows enlarged ovary with decreased/absent Doppler flow 2
• Time-sensitive diagnosis to preserve ovarian function

Ectopic Pregnancy

• Immediate obstetric consultation for methotrexate versus surgical management 2
• Hemodynamic stability determines urgency of intervention

Tubo-Ovarian Abscess

• Broad-spectrum IV antibiotics with anaerobic coverage 2
• Surgical consultation if no clinical improvement within 48-72 hours or if rupture suspected

Critical Pitfalls to Avoid

• Never omit pregnancy testing—failure to obtain β-hCG can result in missed ectopic pregnancy or inappropriate radiation exposure 2
• Do not use CT as first-line for gynecological causes—ultrasound provides equivalent or superior accuracy without radiation 1, 2
• Never order CT pelvis alone—it provides insufficient coverage and must be combined with abdominal imaging 1, 4
• Do not perform non-contrast CT unless specifically evaluating for urolithiasis—IV contrast is essential for detecting inflammatory, vascular, and solid-cystic lesions 4
• Do not dismiss mild or atypical symptoms—many PID cases present with nonspecific symptoms like abnormal bleeding or dyspareunia 2
• Do not delay imaging or surgical consultation due to radiation concerns when maternal or fetal life is threatened—benefits outweigh risks 3