Ectopic Pregnancy
Posted by dkwinter

Source: Academic Life in Emergency Medicine

In descending order, the most significant physical exam findings were: 

  • Cervical motion tenderness (Positive LR = 4.9)
  • Peritoneal findings (Positive LR = 4.2-4.5)
  • Adnexal mass (Positive LR = 2.4)

BETA-HCG:

  • The “discriminatory zone” continues to be debated – no consensus on the number.
  • A one-time hCG level does not rule out ectopic pregnancy.

ULTRASOUND

  • Findings of an intrauterine pregnancy (IUP) such as gestational sac or fetal pole ruled out ectopic pregnancy, except in rare cases of heterotropic prengnacy.
  • Bedside ultrasound is the single most useful diagnostic test. Positive LR = 111. 

JAMA review: Ectopic Pregnancy

Crochet et al. Does this woman have an ectopic pregnancy? 2013; 309(16): 1722-9. PMID 23613077

 

Incidence of heterotopic pregnancy = 0.3-0.8% (1-3% if assisted reproduction)

 

Factoids on Ectopic Pregnancy:

  • Incidence = as high as 2.6%
  • #1 cause of 1st trimester pregnancy-related death
  • 8-31% initially diagnosed as “pregnancy of unknown location” (PUL), despite beta- HCG and ultrasonography
  • More than half of patients with ectopic pregnancy will have ZERO risk factors.

 

Discriminatory zone: Serum beta-HCG level cutoff above which intrauterine pregnancy is likely visible on US.

  • Variable definition of cutoff with range of 1,500-3,000 mIU/mL.
  • No single serum beta-HCG value is predictive of an ectopic pregnancy.
  • If beta-HCG above 3,000 mIU/mL and an “empty uterus” on US, suggestive of ectopic pregnancy.

 

 

Summary measures to detect Ectopic Pregnancy (95% CI)

 

 

Sensitivity

Specificity

LR (+)

LR (-)

Physical exam

• Cervical motion tenderness

0.45

(0.33-0.57)

0.91

(0.80-0.96)

4.9

(1.7-14)

0.62

(0.47-0.83)

• Peritoneal findings

0.23-0.27

0.94-0.95

4.2-4.5

0.78-0.81

• Adnexal mass

0.09

(0.02-0.27)

0.96

(0.92-0.98)

2.4

(1.6-3.7)

0.94

(0.87-1.0)

• Adnexal tenderness

0.61

(0.52-0.69)

0.65

(0.42-0.83)

1.9

(1.0-3.5)

0.57

(0.48-0.67)

Imaging

Transvaginal U/S assessing for ectopic

0.88

(0.52-0.98)

0.99

(0.96-1.0)

111

(12-1,028)

0.12

(0.03-0.55)

 

LR = Likelihood ratio

US = Ultrasonography

 

Conclusion: Transvaginal U/S is the single-best test to assess for ectopic pregnancy.