The presence
of an embryonic heartbeat is an assuring sign
of the health
of the
pregnancy. Once a heartbeat is detected, the chance of the pregnancy continuing ranges from 70-90% dependent on what type of ultrasound is used. If the embryo is less than 5mm CRL, it is possible for it to be healthy without showing a heartbeat, though a follow up scan in 5-7 days should show cardiac activity.