How long can you see the fetal bud fetal heart, how to do?

Generally, after six weeks of pregnancy, pregnant women can only see the fetal bud fetal heart after B ultrasound examination. In early pregnancy, the fetal bud is relatively small, so it is difficult to find it. If a woman still does not find the fetal bud fetal heart after 49 days of pregnancy, it is necessary to pay attention to regular detection to prevent threatened abortion and fetal arrest.