Hello, thanks for using health care magic.
Detection of cardiac activity depends on various factors including age of pregnancy
, sensitivity of the ultrasound
machine, presence of uterine fibroids, obesity and visual acuity of the examiner. Most sensitive machines can detect by 6 weeks.
However, the absence of cardiac activity at an ultrasonographic age corresponding to 7 weeks and with embryonic size greater than 4mm are signs that raise the probability of a missed abortion
However, what you need to do is to get seral levels of beta HCG
twice taken at 48hours interval or to take another ultrasound with another obstetrician to confirm whether its a missed abortion or not.
Best regards and hope this helps you.