when can a baby's heartbeat be detected with internal ultrasound
1 Confirming the presence of your babyâs heartbeat. 2  You may have gone to your doctor with vaginal bleeding or you may be anxious because of problems in a previous pregnancy (such as miscarriage). 3  This ultrasound can routinely detect a heartbeat in your baby as early as 6-7 weeks. transvaginal ultrasound is usually required to see the baby at this stage of the pregnancy. Your baby is just a tiny embryo. Although the ultrasound may see your baby, it measures only a few millimetres long, and it is too early to always detect the babyâs heartbeat.