Can sonographic endometrial pattern be an early indicator for tubal ectopic pregnancy and related tubal rupture?

PURPOSE: The present study aims to determine whether sonographic endometrial pattern can be addressed as an early indicator for tubal ectopic pregnancy and related tubal rupture in case ultrasonography reveals no adnexal mass and maternal serum beta human chorionic gonadotropin (HCG) level is below the discriminatory zone (<or=1,000 mIU/mL).

METHODS: The study evaluated the endometrial features of 441 naturally conceived and asymptomatic first trimester (99 tubal ectopic, 138 failing and 264 normal intrauterine) with maternal serum beta HCG levels<or=1,000 mIU/mL and indeterminate sonographic findings.

RESULTS: Tubal ectopic, failing intrauterine and normal intrauterine pregnancies are statistically similar in aspect of endometrial thickness. However, trilaminar endometrial pattern was significantly less frequent in failing and normal intrauterine pregnancies but significantly more frequent in ruptured tubal pregnancies. Also the relative risk of tubal rupture is significantly higher in case of trilaminar endometrial pattern. Trilaminar endometrial pattern has a sensitivity of 21.2%, specificity of 93.9%, positive predictive value of 50.0% and negative predictive value of 80.5% for distinguishing tubal ectopic pregnancy. Moreover, the sensitivity, specificity, positive and negative predictive values of the same pattern are computed to be 60.0, 95.7, 85.7 and 84.6%, respectively, in the prediction of ruptured tubal pregnancy.

CONCLUSIONS: Sonographic appearance of endometrium may be used to predict tubal pregnancy when ultrasonography shows no adnexal mass and maternal serum HCG<or=1,000 mIU/mL. That is, trilaminar pattern may indicate tubal pregnancy and warn about a possible related rupture in case of previous ectopic pregnancy or pelvic surgery.