How big is the pregnancy sac? You can see the embryo bud.

Normal pregnancy 6 weeks-8 weeks can be seen through B ultrasound fetal heart and embryo, gestational sac size is generally within 1-2 cm can see fetal heart and embryo bud, but if the gestational sac is greater than 3 cm, or do not see fetal heart and embryo bud, more consider is caused by fetal arrest.