Blighted ovum: What are the causes?

A blighted ovum is a common cause of early pregnancy loss. It occurs when a fertilized egg develops a placenta and membrane but no embryo. A blighted ovum usually occurs in the first few weeks of pregnancy — often before a woman even knows she's pregnant. An ultrasound will show an empty gestational sac. Blighted ovum is often due to chromosomal abnormalities in the fertilized egg.

With a blighted ovum, you may miss a period and have a positive pregnancy test. This is because the placenta secretes human chorionic gonadotropin (HCG), a pregnancy hormone. You may also experience some symptoms of pregnancy, such as fatigue and breast tenderness. But later when the placenta stops growing and hormone levels decrease, your pregnancy symptoms will subside. At this point, you may have minor abdominal cramping and light spotting or bleeding.

A blighted ovum will eventually result in miscarriage, although this may not occur for several weeks. Retaining this tissue is not harmful, but waiting for a miscarriage can be distressing. So a doctor may offer medications that will begin the natural process of miscarriage. Another option is a procedure called D and C (dilation and curettage) to remove the placental tissues.

The vast majority of women who have had one miscarriage go on to have successful pregnancies. If you have consecutive miscarriages in the first trimester, your doctor may recommend testing to try to determine the cause.