Ectopic%20pregnancy Diagnosis

History

• Heightened index of suspicion is imperative to facilitate prompt diagnosis prior to catastrophic events
• Thorough review of history can identify risk factors and raise the index of suspicion

Physical Exam

• Tenderness on abdominal palpation and cervical motion on pelvic exam; guarding and rebound tenderness suggest rupture
• Absence of pain or failure to elicit tenderness does not rule out ectopic pregnancy; pelvic exam may be normal in 10% of patients

Diagnostic Studies

Standard Urine Pregnancy Test

• Used as the initial step in diagnosis
• Identifies the presence of human chorionic gonadotropin (hCG) in concentrations as low as 25 mIU/mL

Serum Progesterone

• Viable intrauterine pregnancies (IUP) are associated with serum progesterone level of ≥79.5 nmol/L (25 ng/mL) and at this level, ectopic pregnancy can be excluded (97.5% sensitivity) and no further testing is required
• Nonviable pregnancies, both intrauterine and ectopic, are associated with serum progesterone level of ≤15.9 nmol/L (5 ng/mL)
  • Diagnostic uterine curettage can be performed to check for chorionic villi from incomplete abortion

• Serum progesterone as a diagnostic procedure is limited by the fact that most patients have levels in the gray zone between 15.9-79.5 nmol/L (5-25 ng/mL)
  • There is too much overlap between IUP and ectopic pregnancy in this range

• A meta-analysis demonstrated that a single progesterone level cannot be used to predict an ectopic pregnancy
• Usually, progesterone testing is not a rapid procedure and results are not readily available for use in the emergency department

Serial β-hCG Measurements

• In normal pregnancy, the rise in β-hCG level is gestational age-specific; concentration usually increases 66-67% over a 48-hour interval in the first 6 weeks
• A rate of rise <53-66% over a 48-hour period suggests an abnormally growing IUP or an ectopic pregnancy
• Serum β-hCG level can be used in the planning of expectant and medical management of ultrasound-confirmed ectopic pregnancy 
  
  • When β-hCG level is falling or failed to increase by at least 53-66% in 48 hours and nonviable IUP is suspected, uterine curettage may be performed

• Ectopic pregnancy is suspected when β-hCG fails to decline by at least 15% in 48 hours or no chorionic villi was evacuated via uterine curettage

Ultrasound (US)

• β-hCG testing is usually combined with US
• Tubal ectopic pregnancy is best diagnosed with a transvaginal ultrasound 
• Suspect ectopic pregnancy when
  • Tubal ring is present, which appears as a thick-walled cystic structure in the adnexa independent of the ovary and uterus, or a complex adnexal mass
    • An adnexal mass that moved separate to the ovary identifies a tubal ectopic pregnancy
  • IUP is not detected by abdominal US at serum level above the threshold of 6500 IU/L (6500 mIU/mL)
  • Discriminatory zone level (serum hCG level at which it is assumed that all viable IUP will be visualized by transvaginal US, >1500-2500 IU/L) is dependent upon the experience of the sonographer, quality of the US equipment, prior knowledge of the woman’s symptoms and risks, and the presence of physical factors (eg multiple pregnancy, uterine fibroids)

• Sonographic absence of IUP, positive pregnancy test, fluid in the cul-de-sac, and an abnormal pelvic mass, ectopic pregnancy is almost certain

Culdocentesis

• This technique is considered only in emergent situations when US is unavailable
• Non-clotting bloody fluid aspirated from the cul-de-sac is compatible with the diagnosis of hemoperitoneum resulting from an ectopic pregnancy
• Nondiagnostic since blood in the cul-de-sac may be due to other causes (eg ruptured ovarian cyst)
• May be unsatisfactory in patients with obliterated cul-de-sac from previous salpingitis and pelvic peritonitis; thus, failure to aspirate blood does not rule out ectopic pregnancy

Laparoscopy

• An invasive procedure for definitive diagnosis by complete visualization of the pelvis
• As a diagnostic tool, availability of sensitive non-invasive tests reduced the need for this procedure in ruling out ectopic pregnancy in women with a positive result of pregnancy test