Five weeks of pregnancy without seeing the yolk sac is considered to be a temporary failure to see the normal development of the gestational sac. There are two situations: one is individual differences or the pregnant woman’s own menstrual cycle is relatively long, the current pregnancy time is relatively short; the other is due to poor embryonic development, resulting in the phenomenon of the embryo stops developing. 1. Generally speaking, the yolk sac can be seen at about five to six weeks of pregnancy, if it is not seen at five weeks of pregnancy, it is possible that the pregnancy is still relatively short, you can temporarily observe for a week and check again to see if it can be seen. 2. If you still can’t see the yolk sac after another week, you need to judge according to the blood HCG and progesterone to consider whether it is caused by embryonic dysplasia. In short, when a pregnant woman is five weeks pregnant and does not see the yolk sac development, it is recommended to go to the hospital in time for examination, so as not to cause adverse consequences.