Blob and Bagel sign on Ultrasound can be labelled as definitive for Ectopic Pregnancy

. blob sign of ectopic pregnancy.

Women with the Blob and Bagel ultrasound sign should be reclassified from having ‘probable’ ectopic pregnancy (EP) to ‘definitive’ EP and should be treated as such reports the result of a large retrospective cohort study published March 11, 2018, in Journal of Ultrasound in Obstetrics and Gynecology.

Ectopic Pregnancy is still the leading cause of first-trimester maternal deaths and constitutes 4% of all pregnancy-related deaths. The incidence of ectopic is highest in women undergoing In-Vitro Fertilization(IVF) and ranges from 4% to 11% of all pregnancies.

The broken arrow depicts the right ovary and the solid arrow shows ectopic pregnancy characterized by the ‘bagel sign’.

With the advent of high-resolution transvaginal ultrasound (TVS), more ectopic pregnancies are diagnosed at clinically early and hemodynamically stable stages that are amenable to various modes of management. In modern times TVS has replaced laparoscopy as the diagnostic tool of choice.

Barnhart et al have published a recent consensus statement of nomenclature, definitions, and outcome of pregnancy of unknown location (PUL) in Journal Fertility and Sterility. In which, research papers originating from the US diagnose EP based on findings of an extrauterine gestational sac with the visualization of a yolk sac or embryo, while literature from the UK and European countries diagnose EP based on finding of an extrauterine inhomogeneous mass (blob sign), or an extrauterine empty gestational sac (bagel sign). 

   

This study was undertaken with an aim to determine whether these ultrasound markers can be used to definitely predict EP, instead of just raising a probability of its presence. The study recruited 849 of 7490 consecutive women who attended the Early Pregnancy Unit (EPU) of the Nepean Hospital, Sydney, Australia over a period of 10 years.

At TVS, 240 of 849 women were diagnosed as probable EP, of which 174 (72.5%) exhibited the blob sign and 66 (27.5%) exhibited bagel sign. The rest 609 were labeled as PUL, of which 47 received a final diagnosis of EP (including 24 blob signs, 19 bagel signs and four gestational sacs with embryo/yolk sac.

Nearly 51% of patient with blob sign and 59% of patients with bagel sign underwent laparoscopic salpingectomy, and HPE proved the diagnosis in 97% of patients with blob sign and 96% of patients with bagel sign.

The sensitivity for the blob and bagel signs in the prediction of definite tubal EP was 89.8% and 83.3%, respectively, the specificity was 99.5% and 99.6%, PPV was 96.7% and 95.2% and NPV was 98.3% and 98.6%.

All the parameters were comparable to the corresponding parameters of the extrauterine gestational sac with yolk sac and/or embryo on TVS used in the prediction of definite tubal EP.

The authors concluded that Blob and bagel signs are the commonest presentation of tubal ectopic on TVS, and because of high PPV of >95%, it can be used for the definitive diagnosis of EP. Majority of women who present with EP during early pregnancy can have a definitive diagnosis with only standalone TVS, with laparoscopy being used as the treatment modality.

Abstract

Consensus statement

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