How Early Can You See a Baby on an Ultrasound Scan?

Peek A Baby offers Early Pregnancy Reassurance Scans from 6 weeks of pregnancy.

In viable pregnancies, transvaginal (internal) scans should be able to detect a gestation sac from 5 weeks of pregnancy. A yolk sac can be seen at 5 1/2 weeks gestation.

A transabdominal (external) scan may be less accurate at this early 5-week stage. The quality of ultrasound images produced by both trans-vaginal and trans-abdominal scans will be affected by your BMI and the position of the baby. Higher BMIs can affect the visibility of the pregnancy especially when the pregnancy is so early.

Ultrasound can usually detect a fetal heartbeat at 6-7 weeks of pregnancy when the baby's length or crown-rump length (CRL) is 7mm.

If the CRL is less than 7mm and no heartbeat is seen, this may be because the embryo is too young. You will be offered a re-scan. Often ladies date their pregnancies based on their last period dates however, these dates can be affected by numerous variables and as such, are not always correct. This can mean that the pregnancy is not as far along as suggested by your period dates. We will be able to see the pregnancy, but not be able to confirm a heartbeat and will therefore ask you back for a free rescan at a time when the sonographer recommends.

If the CRL is >7mm and no heartbeat is seen, sadly this means you may have suffered a miscarriage.

Very rarely, your sonographer may be concerned that there are ultrasound signs of an ectopic pregnancy. This is a dangerous complication of pregnancy that requires hospital treatment. In this case, the sonographer will advise you on what to do next.