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Three Part Question

In [pregnant women, who present with vaginal bleeding to the A&E department,] is [transabdominal or transvaginal ultrasound] better at [detecting an ectopic pregnancy]?

Clinical Scenario

A 27 year old women presents to the A&E department with vaginal bleeding. She has a positive pregnancy test, and you wonder what is the best imaging modality to rule out an ectopic pregnancy?

Search Strategy

Medline 1966-06/05 using the ovid interface
Embase 1980-06/05
CINAHL 1982-06/05
The Cochrane Issue 2, 2005
({[tubal pregnancy.mp or exp PREGNANCY, TUBAL or ectopic pregnancy or exp PREGNANCY, ECTOPIC or abdominal pregnancy.mp or exp PREGNANCY, ABDOMINAL or extrauterine pregnancy.mp] AND [ultrasound.mp. or exp Ultrasonography or sonography.mp.] AND [transvaginal.mp. or vaginal.mp. or endovaginal.mp.] AND [abdominal.mp. or transabdominal.mp. or transvesical.mp.]} LIMIT to [english language and human])
Cochrane 'ectopic pregnancy' AND 'ultrasound'

Search Outcome

140 papers were found using medline, of which 10 were relevant. No additional papers found by the other datbases.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Athey PA et al 1991 Oct Canada	45 consecutive cases of proven ectopic pregnancy Transvaginal vs transabdominal ultrasonography Gold standard: ectopic pregnancy was pathologically proven	Diagnostic test study	Ectopic pregnancy (n=45)	TVU superior to TAU in 22 (49%)	Retrospective
				TVU was inferior to TAU in 3 cases (7%)
				In 20 cases (44%) findings were similar
Valenzano M et al 1991 Switzerland	35 patients attending an emergency room with a positive pregnancy test and suspected ectopic pregnancy Transabdominal vs transvaginal ultrasonography Gold standard: ectopic pregnancy was proved surgically and confirmed by histology	Diagnostic test study	Ectopic pregnancy	TVU: Senitivity 88.4%, TAU: Sensitivity 76.9%
				TVU missed 1 EP that was detected by TAU
Kivikoski AI et al 1990 Dec United States	34 patients believed to have ectopic pregnancies, of which 25 had an ectopic pregnancy confirmed Transabdominal and transvaginal ultrasonography Gold standard: Operation	Diagnostic test study	Gestational sac (highly suspicious for EP)	68% of cases were found by transabdominal US and in 84% by transvaginal US. 1 case detected by TAU was missed by TVU	Doesn't say if physicians looked at the scans independently
			A distinct adnexal gestational sac	32%* seen on transabdominal US and 64%* seen transvaginally. *P<0.01
Thorsen MK et al 1990 Aug United States	193 women with the clinical diagnosis of suspected ectopic pregnanc. Transabdominal vs endovaginal sonograms Gold standard: Surgically proved	Diagnostic test study	IUP (n=83)	Endovaginal all 83, Transabdominal 34	Scans were interpreted at time of study.
			Ectopic Pregnancy (n=60)	Endovaginal 23, TAU 13. 3 seen on TAU but not endovaginal
			Missed abortion blighted ovum (n=14)	Endovaginal 7, TAU 5
			Indeterminate	Endovaginal 80 out of 193, TAU 141 out of 193
Cacciatore B et al 1989 May United States	100 women suspected of having an ectopic pregnancy Whrn TAU did not show a living fetus vaginal sonography was performed Gold standard: Histological examination of tissue samples obtained by surgery	Diagnostic test study	Sure IUP; 35 were normal and 26 ended in spontaneous abortion	Vaginal sonography 30, 0 were detected by TAU .P<0.001 One IUP was falsely suspected as being ectopic by both methods
			Sure EP N=39	Vaginal sonography 8 and TAU 0. P<0.05
Jain KA et al 1988 Dec United States	90 women with a positive pregnancy test and signs and symptoms of threatened abortion or ectopic pregnancy Endovaginal vs abdominal sonography Gold standard: Surgical exploration and pathologic confirmation	Diagnostic test study	Ectopic Pregnancy (n=22)	Endovaginal sonography 3, TAU 0	Knowledge of TAU findings made it easier to interpret endovaginal findings Table of results is confusing
Dashefsky SM et al 1988 Oct United States	53 patients who had a positive pregnancy test finding and who were at risk for ectopic pregnancy. Endovaginal vs transvesical US Gold standard: Clinical or pathological	Diagnostic test study	Normal IUP (n=19)	Endovaginal 100%, transvesical 58%	29 Examined retrospectively Physicians were not blinded to the diagnosis
			Abnormal IUP detected	Endovaginal 44%, transvesical 19%
			Live ectopic pregnancy (n=18)	Endovaginal: accuracy 72%, sensitivity 17%, specificity 100% Transvesical: accuracy 68%, sensitivity 6% and specificity 100%
			No IUP	Endovaginal: accuracy 83%*, sensitivity 100% and specificity 74% Transvesical: accuracy 60%*, sensitivity 100% and specificity 40%. *P<0.001, Mcnemar test (n=53)
Pennell RG et al 1987 Oct United States	38 pregnant women with clinical complications, at 5-12 weeks pregnant When TAU was inconclusive endovaginal ultrasound was performed Gold standard: Clinically proven	Diagnostic test study	Ectopic Pregnancy (n=6)	Extrauterine sac seen in 3 case endovaginally but absence of intrauterine gestational sac seen in all 6 cases. For TAU it was 2 and 4 respectively.	Did not state what findings would allow a definate diagnosis of either an IUP or EP

Comment(s)

All the papers included used a relatively small sample size, however, they were all in accordance with each other. Occasionally some ectopic pregnancies were detected by transabdominal ultrasound that were missed by transvaginal ultrasound. This did not happen very often.

Clinical Bottom Line

Transvaginal ultrasound is more sensitive than transabdominal ultrasound at detecting an ectopic pregnancy.

References

1. Qureshi IA. Ullah H. Akram MH. Ashfaq S. Nayyar S Transvaginal versus transabdominal sonography in the evaluation of pelvic pathology. Journal of the College of Physicians & Surgeons - Pakistan 2004;14(7):390-3
2. Athey PA. Lamki N. Matyas MA. Watson AB Jr Comparison of transvaginal and transabdominal ultrasonography in ectopic pregnancy Canadian Association of Radiologists Journal 1991;42(5):349-52
3. Valenzano M. Anserini P. Remorgida V. Brasca A. Centonze A. Costantini S Transabdominal and transvaginal ultrasonographic diagnosis of ectopic pregnancy: clinical implications Gynecologic & Obstetric Investigation 1991;31(1):8-11
4. Gramith F. Sirr S. Hollerman J. Hawks L Transvaginal versus transabdominal sonography in patients suspected of having ectopic pregnancy. Minnesota Medicine 1991;74(1):27-31
5. Kivikoski AI. Martin CM. Smeltzer JS Transabdominal and transvaginal ultrasonography in the diagnosis of ectopic pregnancy: a comparative study. American Journal of Obstetrics & Gynecology 1990;163(1 Pt 1):123-8
6. Thorsen MK. Lawson TL. Aiman EJ. Miller DP. McAsey ME. Erickson SJ. Quiroz F. Perret RS Diagnosis of ectopic pregnancy: endovaginal vs transabdominal sonography American Journal of Roentgenology 1990;155(2):307-10
7. Cacciatore B. Stenman UH. Ylostalo P Comparison of abdominal and vaginal sonography in suspected ectopic pregnancy Obstetrics & Gynecology 1989;73(5 Pt 1):770-4
8. Jain KA. Hamper UM. Sanders RC Comparison of transvaginal and transabdominal sonography in the detection of early pregnancy and its complications American Journal of Roentgenology 1988;151(6):1139-43
9. Dashefsky SM. Lyons EA. Levi CS. Lindsay DJ Suspected ectopic pregnancy: endovaginal and transvesical US Radiology 1988;169(1):181-4
10. Pennell RG. Baltarowich OH. Kurtz AB. Vilaro MM. Rifkin MD. Needleman L. Mitchell DG. Mervis SA. Goldberg BB Complicated first-trimester pregnancies: evaluation with endovaginal US versus transabdominal technique. Radiology 1987;165(1):79-83