When does a blighted ovum happen?

When does a blighted ovum happen?

A blighted ovum causes an early miscarriage in the first trimester of pregnancy. During fetal development, a fertilized egg turns into a blastocyte. At around four weeks of pregnancy, this blastocyte implants in the wall of the uterus and develops into an embryo. When you have a blighted ovum, the gestational sac that would hold the embryo continues to grow, even without an embryo present. The following can occur:

• A blighted ovum happens so early in pregnancy, that you never realize you are pregnant.
• You have a positive pregnancy test and signs of pregnancy only to discover a blighted ovum at your first ultrasound.
• You have a positive pregnancy test and signs of pregnancy but then experience a miscarriage.