An<unk>  should be considered as the cause of abdominal pain or vaginal bleeding in every woman who has a positive pregnancy test. The primary goal of diagnostic procedures in possible<unk>  is to triage according to risk rather than establishing pregnancy location. Transvaginal ultrasonography An ultrasound showing a gestational sac with fetal heart in the fallopian tube has a very high specificity of<unk> . Transvaginal ultrasonography has a sensitivity of at least 90% for<unk> . The diagnostic ultrasonographic finding in<unk>  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 case of hematosalpinx. This sign has been estimated to have a sensitivity of 84% and specificity of 99% in diagnosing<unk> . In the study estimating these values, the blob sign had a positive predictive value of 96% and a negative predictive value of 95%. The visualization of an empty extrauterine gestational sac is sometimes known as the "bagel sign", and is present in around 20% of cases. In another 20% of cases, there is visualization of a gestational sac containing a yolk sac or an embryo.<unk> es where there is visualization of cardiac activity are sometimes termed "viable<unk> ". File:Schematic figure of vaginal ultrasound in<unk> .Transvaginal ultrasonography of an<unk> , showing the field of view in the following image. File:Blob sign of<unk> .A "blob sign", which consists of the<unk> . The ovary is distinguished from it by having follicles, whereof one is visible in the field. This patient had an intrauterine device (IUD) with progestogen, whose cross-section is visible in the field, leaving an ultrasound shadow distally to it. File:Ectopicleftmass.Ultrasound image showing an<unk>  where a gestational sac and fetus has been formed. A pregnancy not in the uterus The combination of a positive pregnancy test and the presence of what appears to be a normal intrauterine pregnancy does not exclude an<unk> , since there may be either a heterotopic pregnancy or a "", which is a collection of within the endometrial cavity that may be seen in up to 20% of women. A small amount of anechogenic-free fluid in the recto-uterine pouch is commonly found in both intrauterine and<unk> es. The presence of echogenic fluid is estimated at between 28 and 56% of women with an<unk> , and strongly indicates the presence of hemoperitoneum. However, it does not necessarily result from tubal rupture but is commonly a result from leakage from the distal tubal opening. As a rule of thumb, the finding of free fluid is significant if it reaches the fundus or is present in the vesico-uterine pouch. A further marker of serious intra-abdominal bleeding is the presence of fluid in the hepatorenal recess of the subhepatic space. Currently, Doppler ultrasonography is not considered to significantly contribute to the diagnosis of<unk> . 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. Ultrasonography and β-hCG Algorithm of the management of a pregnancy of unknown location, that is, a positive pregnancy test but no pregnancy is found on transvaginal ultrasonography. If serum hCG at 0 hours is more than 1000 IU/L and there is no history suggestive of complete miscarriage, the ultrasonography should be repeated as soon as possible. Where no intrauterine pregnancy (IUP) is seen on ultrasound, measuring β-human chorionic gonadotropin (β-hCG) levels may aid in the diagnosis. The rationale is that a low β-hCG level may indicate that the pregnancy is intrauterine but yet too small to be visible on ultrasonography. While some physicians consider that the threshold where an intrauterine pregnancy should be visible on transvaginal ultrasound is around 1500 mIU/ml of β-hCG, a review in the JAMA Rational Clinical Examination Series showed that there is no single threshold for the β-human chorionic gonadotropin that confirms an<unk> . Instead, the best test in a pregnant woman is a high resolution transvaginal ultrasound. The presence of an adnexal mass in the absence of an intrauterine pregnancy on transvaginal sonography increases the likelihood of an<unk>  100-fold (LR+ 111). When there are no adnexal abnormalities on transvaginal sonography, the likelihood of an<unk>  decreases (LR- 0.12). An empty uterus with levels higher than 1500 mIU/ml may be evidence of an<unk> , but may also be consistent with an intrauterine pregnancy which is simply too small to be seen on ultrasound. If the diagnosis is uncertain, it may be necessary to wait a few days and repeat the blood work. This can be done by measuring the β-hCG level approximately 48 hours later and repeating the ultrasound. The serum hCG ratios and logistic regression models appear to be better than absolute single serum hCG level. If the β-hCG falls on repeat examination, this strongly suggests a spontaneous abortion or rupture. The fall in serum hCG over 48 hours may be measured as the hCG ratio, which is calculated as: An hCG ratio of 0.87, that is, a decrease in hCG of 13% over 48 hours, has a sensitivity of 93% and specificity of 97% for predicting a failing pregnancy of unknown location (PUL). The majority of cases of<unk>  will have serial serum hCG levels that increase more slowly than would be expected with an IUP (that is, a suboptimal rise), or decrease more slowly than would be expected with a failing PUL. However, up to 20% of cases of<unk>  have serum hCG doubling times similar to that of an IUP, and around 10% of<unk>  cases have hCG patterns similar to a failing PUL. Other methods Direct examination A laparoscopy or laparotomy can also be performed to visually confirm an<unk> . This is generally reserved for women presenting with signs of an acute abdomen and hypovolemic shock. Often if a tubal abortion or tubal rupture has occurred, it is difficult to find the pregnancy tissue. A laparoscopy in very early<unk>  rarely shows a normal-looking fallopian tube. Culdocentesis Culdocentesis, in which fluid is retrieved from the space separating the vagina and rectum, is a less commonly performed test that may be used to look for internal bleeding. In this test, a needle is inserted into the space at the very top of the vagina, behind the uterus and in front of the rectum. Any blood or fluid found may have been derived from a ruptured<unk> . Progesterone levels Progesterone levels of less than 20 nmol/l have a high predictive value for failing pregnancies, whilst levels over 25 nmol/l are likely to predict viable pregnancies, and levels over 60 nmol/l are strongly so. This may help in identifying failing PUL that are at low risk and thereby needing less follow-up. Inhibin A may also be useful for predicting spontaneous resolution of PUL, but is not as good as progesterone for this purpose. Mathematical models There are various mathematical models, such as logistic regression models and Bayesian networks, for the prediction of PUL outcome based on multiple parameters. Mathematical models also aim to identify PULs that are low risk, that is, failing PULs and IUPs. Dilation and curettage Dilation and curettage (D&C) is sometimes used to diagnose pregnancy location with the aim of differentiating between an<unk>  and a non-viable IUP in situations where a viable IUP can be ruled out. Specific indications for this procedure include either of the following: * No visible IUP on transvaginal ultrasonography with a serum hCG of more than 2000 mIU/ml. * An abnormal rise in hCG level. A rise of 35% over 48 hours is proposed as the minimal rise consistent with a viable intrauterine pregnancy. * An abnormal fall in hCG level, such as defined as one of less than 20% in two days. Classification Tubal pregnancy The vast majority of<unk> es implant in the Fallopian tube. Pregnancies can grow in the fimbrial end (5% of all<unk> es), the ampullary section (80%), the isthmus (12%), and the cornual and interstitial part of the tube (2%). Mortality of a tubal pregnancy at the isthmus or within the uterus (interstitial pregnancy) is higher as there is increased vascularity that may result more likely in sudden major internal bleeding. A review published in 2010 supports the hypothesis that tubal<unk>  is caused by a combination of retention of the embryo within the fallopian tube due to impaired embryo-tubal transport and alterations in the tubal environment allowing early implantation to occur. Nontubal<unk>  Two percent of<unk> es occur in the ovary, cervix, or are intra-abdominal. Transvaginal ultrasound examination is usually able to detect a cervical pregnancy. An ovarian pregnancy is differentiated from a tubal pregnancy by the Spiegelberg criteria. While a fetus of<unk>  is typically not viable, very rarely, a live
Ectopic pregnancy
Miscarriage
Ovarian torsion
Appendicitis
Tubo-ovarian abscess
Ovarian cyst
Ovarian pregnancy
Dysmenorrhea