Hello , Welcome to Healthcare Magic forum. Please do not panic. The developing fetus is seen inside the gestational sac formed by the uterus in the form of a fetal pole or embryo covered with yolk sac. However sometimes if ultrasound is done in early gestation first month it can be too early to visualise a fetal pole. The fetal pole becomes visible in a transvaginal ultrasound somewhere between 5 to 6 weeks of gestational age, but any small error in dating the pregnancy can cause non visualisation of fetus. The yolk sac is the first thing to become visible inside the gestational sac on a transvaginal ultrasound, appearing at an average of 5.5 to 6 weeks gestational age.When an ultrasound shows no yolk sac, the reason may be miscarriage but it could also be that the pregnancy is still early. In a viable pregnancy, the yolk sac and possibly the fetal pole will always become visible on a followup ultrasound which may be ordered by your doctor in another weekto ten days. When a followup ultrasound does not show continued development and the appearance of a yolk sac, your doctor will diagnose miscarriage or a blighted ovum. So in your case when you are faced with an ultrasound that shows no yolk sac, you will probably be told to wait for a followup ultrasound. The wait can be very difficult, naturally, but is necessary for an accurate diagnosis. Wishing you all the best . Regards