Related Experiment Video
Updated: Feb 5, 2026

A Novel Use of Three-dimensional High-frequency Ultrasonography for Early Pregnancy Characterization in the Mouse
Published on: October 24, 2017
[ENDOMETRIAL-PATTERN IN EARLY PREGNANCY AND CORRELATION WITH ECTOPIC-PREGNANCY]
Sama Yasin1, Yael Sciaky-Tamir1,2, Emad Mostafa1
1Ultrasound Unit, Department of Obstetrics and Gynecology, Ziv Medical Center, Zefat, Israel.
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.
Related Concept Videos
Correlations
Correlation and Causation
Correlation versus Causation
If the dependent variable increases or decreases when the independent variable increases, there is a positive or negative...
Correlation
Two variables, for example, a and b, are said to be positively correlated if both variables move in the same direction. In other words, a positive correlation exists between two variables, a and b, if:
Fixed Action Patterns
Correlation and Regression
Coefficient of Correlation
If you suspect a linear relationship between x and y, then r can measure how strong the linear relationship is.
What the VALUE of r tells us:
The value of r is always between –1 and +1: –1 ≤ r ≤ 1.
The size of the correlation r indicates the...

