Hum. Reprod. Advance Access originally published online on September 13, 2007
Human Reproduction 2007 22(11):2824-2828; doi:10.1093/humrep/dem283
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The diagnostic effectiveness of an initial transvaginal scan in detecting ectopic pregnancy
1 Early Pregnancy and Gynaecological Ultrasound Unit, Department of Obstetrics and Gynaecology, St George's, University of London, Cranmer Terrace, London SW17 0RE, UK 2 Fetal Medicine Unit, Department of Obstetrics and Gynaecology, St George's, University of London, London, UK 3 Early Pregnancy and Advanced Endosurgery Unit, Nepean Clinical School, Nepean Hospital, University of Sydney, Sydney, Australia 4 Department of Obstetrics and Gynaecology, University Hospitals, KU Leuven, Belgium
5 Correspondence address. Tel: +44-208-725-0050; Fax: +44-208-725-0094; E-mail: ejkirk{at}hotmail.co.uk
BACKGROUND: To determine the effectiveness of an initial transvaginal ultrasound scan (TVS) in the detection of ectopic pregnancy in consecutive women attending an early pregnancy unit (EPU).
METHODS: This was a prospective observational study. Unselected women attending a dedicated EPU underwent a TVS. Women were classified as having an intrauterine pregnancy (IUP), ectopic pregnancy or pregnancy of unknown location (PUL). Women with a PUL were followed up until the final location of the pregnancy was determined. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) with 95% confidence intervals (CIs) for the initial TVS in the diagnosis of ectopic pregnancy were calculated.
RESULTS: During a one-year study period, 5318 consecutive women attended the EPU. Outcome data were available for 5240 (98.5%) women. Of these, the initial TVS showed an IUP in 4693 (89.6%) cases and an ectopic pregnancy in 91 (1.7%) cases. The remaining 456 (8.7%) women were classified as PUL, and of these 31 (6.8%) were subsequently found to have ectopic pregnancies. The overall sensitivity of the initial TVS in the diagnosis of ectopic pregnancy was 73.9% (95% CI: 65.1–81.6) with a specificity of 99.9% (95% CI: 99.8–100), a PPV of 96.7% (95% CI: 90.7–99.3) and an NPV of 99.4% (95% CI: 99.2–99.6).
CONCLUSIONS: In unselected women attending an EPU, pregnancy location can be diagnosed accurately in over 90% of all pregnancies and in 73.9% of ectopic pregnancies with a single TVS.
Key words: transvaginal ultrasound/ectopic pregnancy/intrauterine pregnancy/pregnancy of unknown location
Submitted on April 15, 2007; resubmitted on June 15, 2007; accepted on June 20, 2007.