Abnormal sonographic appearances of the yolk sac: which can be associated with adverse perinatal outcome?

AIMS: The present study aimed to determine whether yolk sacs with abnormal sonographic appearance are associated with adverse perinatal outcomes in both early and late gestation. MATERIAL AND METHODS: A total of 305 viable singleton pregnancies with gestational age of 6 to 9 weeks were prospectively evaluated with respect to perinatal outcomes and sonographic characteristics of the yolk sacs. RESULTS: An abnormal yolk sac was found in 66 pregnancies. In pregnancies with enlarged yolk sacs a miscarriage occurred in 37.5% of cases (3/8). The pregnancies with a yolk sac diameter >/= 5 mm had a significantly higher risk of miscarriage (p = 0.005). The risk of miscarriage was statistically similar between the pregnancies with regular and those with irregular yolk sacs (p = 0.73). Miscarriage occurred in 3.8% of pregnancies with irregular yolk sacs (2/52) and none of pregnancies with echogenic yolk sacs (0/6). Adverse perinatal outcomes were not associated with either irregular or echogenic yolk sacs. CONCLUSIONS: An enlarged yolk sac visualized before the 7th week of gestation is strongly associated with a significantly increased risk for spontaneous miscarriage. The presence of an echogenic or irregular yolk sac appears to be unrelated to adverse perinatal outcome.

Decreased echogenicity of the embryo is correlated with absence of cardiac activity.

PURPOSE: The purpose of this study was to investigate whether the sonographic echogenicity of embryos is associated with cardiac activity in utero. METHODS: The present study reviewed a total of 164 embryos having a gestational age between 6 and 8 weeks. These embryos were examined by transvaginal ultrasonography and a comparison of their echogenicity was made with respect to those of the placenta and the myometrium. Grade II embryos were less echogenic than the placenta or had similar echogenicity with the myometrium, whereas grade I embryos shared the same echogenicity as the placenta. In contrast, grade III embryos were less echogenic than the myometrium. RESULTS: Most of the embryos with cardiac activity were detected to have grade II echogenicity (78/130, 60.0%), whereas the remaining embryos had grade I echogenicity (52/130, 40.0%). In contrast, most of the embryos without cardiac activity had grade III echogenicity (20/34, 58.8%), whereas the remaining embryos had either grade II (8/34, 23.5%) or grade I (6/34, 17.7%) echogenicity. CONCLUSIONS: Decreased echogenicity of embryos on grayscale ultrasound in the early first trimester is correlated with an absence of cardiac activity.