Blighted ovum (anembryonic pregnancy)
What is Blighted ovum (anembryonic pregnancy)?
A blighted ovum, also called an anembryonic pregnancy, happens when a fertilized egg implants in the uterus but never develops into an embryo. The gestational sac forms and begins to grow, but the space inside remains empty. Your body produces pregnancy hormones and you may feel pregnant, even though no baby is developing.
This type of early pregnancy loss accounts for about 50% of first trimester miscarriages. It typically occurs in the first 8 to 13 weeks of pregnancy. Most people discover a blighted ovum during a routine ultrasound between 7 and 9 weeks. The ultrasound shows an empty gestational sac where an embryo should be visible.
A blighted ovum is not caused by anything you did or did not do. It happens before most people even know they are pregnant. Your body usually recognizes the problem and ends the pregnancy naturally through miscarriage. Understanding what happened can help you plan for a healthy pregnancy in the future.
Symptoms
- Positive pregnancy test followed by bleeding or spotting
- Cramping in the lower abdomen
- Heavy vaginal bleeding with clots or tissue
- Sudden decrease in pregnancy symptoms like breast tenderness or nausea
- Lower than expected hCG levels for gestational age
- Empty gestational sac on ultrasound after 6 to 7 weeks
Many people with a blighted ovum have no symptoms at first. Early pregnancy symptoms may feel completely normal. You might not know anything is wrong until a routine ultrasound or blood test shows the problem.
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Causes and risk factors
A blighted ovum usually results from chromosomal abnormalities in the fertilized egg. These genetic errors happen randomly during cell division in the very early stages of conception. When the cells contain abnormal chromosomes, the embryo cannot form properly and development stops. Your body recognizes this and prevents further growth.
Poor quality sperm or egg cells can increase the risk of chromosomal problems. Advanced maternal age, over 35 years, is linked to higher rates of chromosomal abnormalities. Other factors include uncontrolled diabetes, exposure to toxins, and certain autoimmune conditions. Most cases happen randomly and are not preventable. Having one blighted ovum does not mean you will have another.
How it's diagnosed
Diagnosis begins with blood tests that measure human chorionic gonadotropin, or hCG. This pregnancy hormone normally rises quickly in early pregnancy, doubling every 48 to 72 hours. With a blighted ovum, hCG levels may be lower than expected for gestational age or fail to rise properly. Serial hCG tests taken a few days apart help track whether levels are increasing as they should.
Ultrasound confirms the diagnosis when it shows an empty gestational sac. By 6 to 7 weeks of pregnancy, an embryo with a heartbeat should be visible on transvaginal ultrasound. If the sac measures larger than 25 millimeters with no embryo inside, or if no embryo appears by 7 weeks, a blighted ovum is diagnosed. Rite Aid offers hCG testing as an add-on to help monitor early pregnancy health. Your doctor will use both blood tests and ultrasound together to make the diagnosis.
Treatment options
- Expectant management, waiting for natural miscarriage to occur on its own
- Medication such as misoprostol to help the uterus pass the pregnancy tissue
- Dilation and curettage, a surgical procedure to remove tissue from the uterus
- Pain relief with ibuprofen or acetaminophen during miscarriage
- Rest and recovery time, both physical and emotional
- Follow-up hCG tests to confirm levels return to zero
- Wait 1 to 3 menstrual cycles before trying to conceive again
- Prenatal vitamins with folate when planning future pregnancy
- Emotional support through counseling or support groups
Need testing for Blighted ovum (anembryonic pregnancy)? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
No, a blighted ovum cannot become a normal pregnancy. Once the gestational sac forms without an embryo, an embryo will not develop later. The pregnancy will end in miscarriage, either naturally or with medical help. If you receive this diagnosis, waiting for a different outcome will not change the result.
Natural miscarriage can take anywhere from a few days to 4 weeks after diagnosis. Some people miscarry within a week, while others wait several weeks with no bleeding. The timing varies based on your body and how far along the pregnancy was. Your doctor can discuss medication or surgical options if you prefer not to wait.
Most people who have one blighted ovum go on to have healthy pregnancies. The risk of recurrence is low, around 1 to 2%. Blighted ovum usually happens because of random chromosomal errors, not an ongoing problem. If you have multiple losses, your doctor may recommend testing to look for underlying causes.
There is no single hCG number that confirms a blighted ovum. Instead, doctors look at how hCG levels change over time. In healthy pregnancy, hCG doubles every 48 to 72 hours in early weeks. Levels that rise slowly or plateau can suggest a problem. Ultrasound confirmation is needed for diagnosis.
At 5 weeks, it may be too early to diagnose a blighted ovum with certainty. The gestational sac is visible, but the embryo may not show up yet. Most doctors wait until 6 to 7 weeks for a clear diagnosis. A follow-up ultrasound a week or two later provides more definitive information.
No, not everyone with a blighted ovum experiences bleeding right away. Some people have no symptoms until miscarriage begins. Others discover the diagnosis during a routine ultrasound while feeling completely normal. Bleeding and cramping usually start when the body begins to pass the pregnancy tissue.
A chemical pregnancy is a very early loss that happens before 5 weeks, often before an ultrasound can see a gestational sac. A blighted ovum occurs later, after the gestational sac has formed but before an embryo develops. Both involve early pregnancy loss but at different stages of development.
No, stress and exercise do not cause a blighted ovum. This type of pregnancy loss results from chromosomal abnormalities that occur at conception. Normal physical activity and everyday stress do not create these genetic errors. You did nothing to cause this outcome.
Most doctors recommend waiting for 1 to 3 menstrual cycles before trying again. This gives your body time to heal physically and allows your hormone levels to return to normal. Waiting also helps establish an accurate due date for your next pregnancy. Talk with your doctor about the right timing for your situation.
Genetic testing is usually not needed after one blighted ovum. Most cases happen randomly and do not repeat. If you experience two or more pregnancy losses, your doctor may recommend testing for you and your partner. Recurrent losses can sometimes point to a treatable underlying condition.