how early can a blighted ovum be detected?
Blighted ova are the cause of nearly half of all miscarriages that occur during the first trimester. Diagnosis of a Blighted Ovum. Examinations conducted on pregnant women early in pregnancy will seldom detect a blighted ovum, even with ultrasound. It is only later, after the baby is supposed to have grown large enough to be visible (which should be by the sixth week of pregnancy), that a diagnosis of blighted ovum can be made.