Correlation between pathologic and ultrasound findings in first trimester spontaneous abortions

We compared the pathologic and ultrasonographic findings of 31 first trimester spontaneous abortions to determine the benefits of such studies. The ultrasound diagnoses included empty gestational sac (n = 11), intrauterine fetal death (n = 11), abortion in progress or incomplete abortion (n = 8), and live embryo (n = 1). Two subgroups of empty sacs were identified by pathologic examination. Embryonic development appeared to be more advanced in one group as indicated by the presence of embryonic red blood cells (RBC's) in the placental vessels. Although an embryo or fetus was identified more frequently by sonar than by pathologic examination, we were able to diagnose developmental anomalies in small embryos that current ultrasound equipment cannot resolve. Such anomalies were identified even in the presence of fetal heart activity. Pathologic examination was also informative when heavy bleeding obscured the contents of the uterine cavity to sonar and was thus supplementary of a suboptimal ultrasound examination. Placental examination proved to be reliable in assessing gestational age at the time of embryonic/fetal death. There was a good correlation between RBC morphology and sonographic measurement of crown-rump length. First trimester ultrasound and pathologic examination of the embryo and placenta are informative and complement each other.