This ultrasound image of early 1st trimester pregnancy shows a large yolk sac within the gestation sac in the uterine cavity. Both abnormally large or small yolk sacs are associated with poor prognosis and usually end in embryonic demise. No embryo was visualized in this case. A yolk sac diameter of greater than 5.6 mm. before 10 weeks gestational age indicates bad prognosis. In this case the yolk sac measured 10.6 mm. (This sonographic image is courtesy of Dr. Durr e Sabih, Pakistan).