during my first u/s a yolk sac was seen and fetal pole could not be visualised and gestational age was 6w 6d, and was asked to repeat scan after 1 week . in my second u/s , gestational age is 7w 2d, yolk sac seen and shows 3 in number measures 5mm to 6mm, but the fetal pole could not be seen, could u plz tell me why is this so and is there any problem with this? plz help me as soon as possible