You are 4 weeks pregnant and had a scan today you the sack but no baby on is this normal?

At 4 weeks of pregnancy, it is common for an ultrasound to show the gestational sac but not a visible embryo. The embryo is usually too small to be detected at this stage. The gestational sac is the fluid-filled structure in the uterus that surrounds the developing embryo. As the pregnancy progresses, the embryo will continue to grow and develop within the gestational sac. By 6-7 weeks of pregnancy, the embryo should be visible on an ultrasound. If you are concerned about the progress of your pregnancy, it is recommended to consult with your doctor.