Editing Ectopic pregnancy (section)

=== Transvaginal ultrasonography ===

An [[ultrasound]] showing a [[gestational sac]] with the fetal heart in the fallopian tube has a very high specificity of ectopic pregnancy. It involves a long, thin transducer, covered with the conducting gel and a plastic/latex sheath and inserted into the vagina.<ref>{{Cite web |date=8 August 2021 |title=Pelvic Ultrasound |url=https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pelvic-ultrasound |access-date=2022-04-26 |website=www.hopkinsmedicine.org |language=en}}</ref> [[Vaginal ultrasonography|Transvaginal ultrasonography]] has a sensitivity of at least 90% for ectopic pregnancy.<ref name=kirk2013/> The diagnostic ultrasonographic finding in ectopic pregnancy is an adnexal mass that moves separately from the ovary. In around 60% of cases, it is an inhomogeneous or a noncystic adnexal mass sometimes known as the "blob sign". It is generally spherical, but a more tubular appearance may be seen in the case of [[hematosalpinx]]. This sign has been estimated to have a sensitivity of 84% and specificity of 99% in diagnosing ectopic pregnancy.<ref name=kirk2013/> In the study estimating these values, the blob sign had a [[Positive and negative predictive values|positive predictive value]] of 96% and a [[Positive and negative predictive values|negative predictive value]] of 95%.<ref name=kirk2013/> The visualization of an empty extrauterine gestational sac is sometimes known as the "bagel sign", and is present in around 20% of cases.<ref name=kirk2013/> In another 20% of cases, there is visualization of a gestational sac containing a yolk sac or an embryo.<ref name=kirk2013/> Ectopic pregnancies where there is visualization of cardiac activity are sometimes termed "viable ectopic".<ref name=kirk2013/>
<gallery mode="packed">
File:Schematic figure of vaginal ultrasonography in ectopic pregnancy.svg|[[Transvaginal ultrasonography]] of an ectopic pregnancy, showing the field of view in the following image
File:Blob sign of ectopic pregnancy.png|A "blob sign", which consists of the ectopic pregnancy. The ovary is distinguished from it by having follicles, whereof one is visible in the field. This patient had an [[intrauterine device with progestogen|intrauterine device (IUD) with progestogen]], whose cross-section is visible in the field, leaving an ultrasound shadow distally to it.
File:Ectopicleftmass.PNG|Ultrasound image showing an ectopic pregnancy where a [[gestational sac]] and fetus have been formed
</gallery>
[[File:UOTW 61 - Ultrasound of the Week 1.jpg|thumb|A pregnancy not in the uterus<ref>{{Cite web |date=14 October 2015 |title=UOTW#61 - Ultrasound of the Week |url=https://www.ultrasoundoftheweek.com/uotw-61/ |url-status=live |archive-url=https://web.archive.org/web/20170509152013/https://www.ultrasoundoftheweek.com/uotw-61/ |archive-date=9 May 2017 |website=Ultrasound of the Week}}</ref>]]
The combination of a positive pregnancy test and the presence of what appears to be a normal intrauterine pregnancy does not exclude ectopic pregnancy, since there may be either a [[heterotopic pregnancy]] or a "{{visible anchor|pseudosac}}", which is a collection of within the endometrial cavity that may be seen in up to 20% of women.<ref name=kirk2013/>

A small amount of [[Echogenicity|anechogenic]]-free fluid in the [[recto-uterine pouch]] is commonly found in both intrauterine and ectopic pregnancies.<ref name=kirk2013/> The presence of [[echogenic]] fluid is estimated at between 28 and 56% of women with an ectopic pregnancy, and strongly indicates the presence of [[hemoperitoneum]].<ref name=kirk2013/> However, it does not necessarily result from tubal rupture but is commonly a result from leakage from the [[distal tubal opening]].<ref name=kirk2013/> As a rule of thumb, the finding of free fluid is significant if it reaches the [[Fundus (uterus)|fundus]] or is present in the [[vesico-uterine pouch]].<ref name=kirk2013/> A further marker of serious intra-abdominal bleeding is the presence of fluid in the [[Hepatorenal recess of subhepatic space|hepatorenal recess of the subhepatic space]].<ref name=kirk2013/>

Currently, [[Doppler ultrasonography]] is not considered to significantly contribute to the diagnosis of ectopic pregnancy.<ref name=kirk2013/>

A common misdiagnosis is of a normal intrauterine pregnancy is where the pregnancy is implanted laterally in an [[arcuate uterus]], potentially being misdiagnosed as an [[interstitial pregnancy]].<ref name=kirk2013/>