In viable pregnancies, trans-vaginal (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. Trans-abdominal (external) scan may be less accurate at this early 5 week stage.

How early can a viable pregnancy be detected?

It can also be used to determine if you have experienced a very early miscarriage. 1 In viable pregnancies, transvaginal ultrasound should be able to detect the gestational sac by 5 weeks gestational age.

When does the risk of miscarriage drop?

Once a pregnancy makes it to 6 weeks and has confirmed viability with a heartbeat, the risk of having a miscarriage drops to 10 percent . According to a 2008 study , the risk for miscarriage falls quickly with further gestational age.