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.
