When does a baby start to show on an ultrasound scan?

Fetal ultrasound: Usually 8 weeks, on a typical ultrasound. On a transvaginal ultrasound the fetal sac may be visible as early as 5 weeks but this is the size of a grain of rice.

Baby or Pregnancy?: The first signs of pregnancy on a trans-vaginal ultrasound can be seen at four and a half (4-1/2) weeks. The embryo is visible by six and a half (6-1/2) weeks and though it certainly doesn't look like a baby yet, the heartbeat can usually be seen by then.