RESUMO
INTRODUCTION: Ectopic-pregnancy is a leading cause of pregnancy-related maternal death in the first trimester. Early sonographic diagnostic ability of ectopic-pregnancy is limited. There is an increasing need to identify sonographic markers that can assist with the diagnosis. OBJECTIVES: To characterize the endometrial-pattern by transvaginal-ultrasound as an early marker for ectopic-pregnancy, before demonstration of tubal mass. METHODS: A multicenter prospective study that included 52 women with a positive HCG test, referred to the ultrasound-unit with a diagnosis of pregnancy of unknown location. A transvaginal ultrasound was performed focusing on the endometrial-pattern, and classifying findings into four categories: homogeneous, heterogeneous, three-laminar and existence of fluid collection within the endometrial cavity. RESULTS: A total of 38 women were diagnosed with ectopic-pregnancy. Three women demonstrated normal intrauterine pregnancy, 3 others had an early miscarriage and 8 women were excluded from the study. No statistically significant differences were found between the groups in terms of demographic, clinical, or laboratory characteristics. Three-laminar pattern had 94% positive predictive value and 18% negative predictive value for ectopic-pregnancy, with sensitivity and specificity of 42% and 83%, respectively. Changes in the endometrial-pattern were demonstrated during subsequent tests when performed. CONCLUSIONS: The use of transvaginal-ultrasound to identify the endometrial-pattern in early pregnancy does not require significant expertise. The identification of three-laminar endometrium in pregnancies of an unknown location, should raise the suspicion of ectopic-pregnancy. DISCUSSION: Three-laminar pattern has high PPV for predicting ectopic pregnancy in women with pregnancy of an unknown location. The changes in the endometrial-pattern during subsequent tests, especially the transition of three-laminar into homogeneous pattern, a phenomenon not reported in previous studies, raised the need for further studies.