A blighted ovum or anembryonic pregnancy is a type of early miscarriage which occurs when a fertilised egg implants in the uterus but doesn't develop into an embryo. It is also referred to as embryonic demise or embryo loss and is a common cause of early pregnancy failure or miscarriage. It can often occur so early that you don't even know you are pregnant.
A blighted ovum is a common cause of miscarriage in the first trimester of pregnancy. A miscarriage is when a pregnancy ends on its own within the first 23 weeks.
When a woman becomes pregnant, the fertilised egg attaches to the uterine wall. At about five to six weeks of pregnancy, an embryo should be present. With a blighted ovum, though, the pregnancy sac forms and grows, but the embryo does not develop. That's why a blighted ovum is also called an anembryonic pregnancy.
What causes a blighted ovum?
Miscarriages from a blighted ovum are often due to problems with chromosomes, the structures that carry genes. This may be from a poor-quality sperm or egg. Or, it may occur due to abnormal cell division. Regardless, your body stops the pregnancy because it recognises this abnormality.
Around two thirds of early miscarriages are due to chromosome abnormalities.
It's important to understand that you have done nothing to cause this miscarriage and you almost certainly could not have prevented it. For most women, a blighted ovum occurs only once.
Signs of a blighted ovum
With a blighted ovum, you may have experienced signs of pregnancy. For example, you may have had a positive pregnancy test or a missed period. With a blighted ovum, hormone levels may remain high for some time after the embryo has stopped developing and is no longer present, so pregnancy tests can still be positive and a woman may still feel pregnant.
Then you may have signs of a miscarriage, such as:
- Abdominal cramps
- Vaginal spotting or bleeding
- A period that is heavier than usual
If you're experiencing any of these signs or symptoms, you may be having a miscarriage. However, not all bleeding in the first trimester ends in miscarriage. Seek medical advice if you have any of these signs.
Diagnosing a blighted ovum
If you thought you had a normal pregnancy, you're not alone; many women with a blighted ovum think so because their pregnancy test remains positive and they still feel pregnant.
For this reason, an ultrasound test is usually needed to diagnose a blighted ovum -- to confirm that the pregnancy sac is empty.
What happens after a miscarriage?
If you have received a diagnosis of a blighted ovum, discuss with your doctor what to do next. Some women have a procedure like a dilation and curretage (D&C), called an ERPC (evacuation of retained products of conception). This surgical procedure involves dilating the cervix and removing the contents of the uterus. Because an ERPC immediately removes any remaining tissue, it may help you with mental and physical closure. It may also be helpful if you want a pathologist to examine tissues to confirm the reason for the miscarriage.
Using a medication such as misoprostol on an outpatient basis may be another option. However, it may take several days for your body to expel all tissue. With this medication, you may have more bleeding and side effects. With both options, you may have pain or cramping that can be treated.
Other women prefer to forego medical management or surgery. They choose to let their body pass the tissue by itself. This is mainly a personal decision, but discuss it with your doctor.