A baby's heartbeat can usually be detected at 6 1/2 to 7 weeks into the pregnancy, according to the American Pregnancy Association. A healthy heartbeat at this stage of fetal development ranges from 90 to 110 beats per minute.
Viability of the fetus can also usually be determined at this stage of the pregnancy. The American Pregnancy Association states that once the baby's heartbeat can be detected, the chance of it continuing to develop ranges from 70 to 90 percent, depending on what type of ultrasound testing was used for detecting the heartbeat. The gestational sac and fetal pole are also visible at this stage.