A blighted ovum (also known as “anembryonic pregnancy”) happens when a fertilized egg attaches itself to the uterine wall, but the embryo does not develop. Cells develop to form the pregnancy sac, but not the embryo itself. A blighted ovum occurs within the first trimester, often before a woman knows she is pregnant. A high level of chromosome abnormalities usually causes a woman’s body to naturally miscarry.

A blighted ovum is the cause of about 50% of first trimester miscarriages and is usually the result of chromosomal problems. A woman’s body recognizes abnormal chromosomes in a fetus and naturally does not try to continue the pregnancy because the fetus will not develop into a healthy baby. This can be caused by abnormal cell division, or poor quality sperm or egg.

Unfortunately, in most cases a blighted ovum cannot be prevented. Some couples will seek out genetic testing if multiple early pregnancy loss occurs. A blighted ovum is often a one time occurrence, and rarely will a woman experience more than one. Most doctors recommend couples wait at least 1-3 regular menstrual cycles before trying to conceive again after any type of miscarriage.

A blighted ovum can occur very early in pregnancy, before most women even know that they are pregnant. You may experience signs of pregnancy such as a missed or late menstrual period and even a positive pregnancy test. Many women assume their pregnancies are on track because their hCG levels are increasing.

The placenta can continue to grow and support itself without a baby for a short time, and pregnancy hormones can continue to rise, which would lead a woman to believe she is still pregnant. A diagnosis is usually not made until an ultrasound test shows either an empty womb or an empty gestational sac.

It is possible that you may have minor abdominal cramps, minor vaginal spotting or bleeding.