الفهرس 
Definition, Incidence And Clinical Types Of Pregnancy Of Unknown LocationOnly 14 pages are availabe for public view
Abstract
T
he more liberal use of home pregnancy tests and access to early pregnancy Assessment units (EPAU) have led to an increase in the number of women undergoing early transvaginal ultrasound scans (TVS) to locate, date and confirm viability of their pregnancy. This approach has resulted in more women being diagnosed with a pregnancy of unknown location (PUL) or inconclusive scan (an empty uterus and no adnexal mass on TVS). This group of women is defined as having a positive pregnancy test and no sign of intra or extrauterine pregnancy on TVS (Gevaert O et al., 2006).
Assessment of early pregnancy is indicated in women with clinical symptoms suggestive of miscarriage or ectopic pregnancy. With transvaginal ultrasound, it is possible to visualize early pregnancy in the majority of women (Bateman B et al., 1990).
Failing intrauterine pregnancies are regarded as a common gynecological cause of abdominal pain and vaginal bleeding, which should be distinguished from ectopic pregnancy (Condous G et al., 2006). Therefore, several methods including clinical and sonographic evidence have been proposed to aid in deferential diagnosis between these two conditions (Bourne T et al., 1997).
Pregnancy causes a choriodecidual reaction in the endometrium, producing the sonographic appearance of the echogenic trophoblastic endometrium. Therefore, one could hypothesize that because the endometrial decidual response depends on the gestational hormonal milieu, a thin endometrial thickness may predict abnormal pregnancy outcome at an early gestational age (Dart R et al., 1999).
Some studies showed that the thinnest endometrial measurements are seen in patients with ectopic pregnancies (Spandorfer S et al 1996). However, their enrolment criteria limited patients to those with β-human chorionic gonadotrophin (β-hCG) levels <1500 mIU/mL. Other studies found no threshold for endometrial thickness to distinguish among patients with ectopic pregnancy, spontaneous miscarriage or early IUP (Mol B et al., 1999), (Mehta T et al., 1999), (Banerjee S et al., 1999), (Seeber B et al., 2007), (Condous G et al., 2005) and (Col-Madendag I et al., 2010).
The relative proportions of PULs are determined by many factors, with the quality of ultrasound examination probably being the most important one. There is a consensus that modern early pregnancy units should strive to maintain a PUL rate of 15% or less. This is still a relatively high figure, and management of women with PUL therefore forms a significant part of the workload in most early pregnancy units (Condous G et al., 2006).