GUIDE
A blighted ovum (anembryonic pregnancy) occurs when a fertilized egg implants in the uterus and a gestational sac develops, but the embryo never forms or stops developing very early.
A blighted ovum is one of the most common causes of miscarriage in the first trimester. It is caused by chromosomal abnormalities that occur at random — not by anything you did. Understanding the diagnosis can help you make informed decisions about management and prepare for the future.
Be prepared from day one
After fertilization, the cells that will become the placenta and the cells that will become the embryo develop separately. In a blighted ovum, the placental cells develop normally — they implant in the uterus, form a gestational sac, and produce hCG (the pregnancy hormone). But the embryonic cells fail to develop due to chromosomal abnormalities. The result is an empty gestational sac.
Because the placental cells are producing hCG, a pregnancy test will be positive. You will experience normal early pregnancy symptoms — nausea, breast tenderness, fatigue — because your body is responding to the pregnancy hormones. There is no way to know from symptoms alone that the embryo has not developed.
A blighted ovum is usually diagnosed on ultrasound between 7 and 9 weeks when the provider looks for an embryo inside the gestational sac and finds it empty. This is often a devastating surprise at what was expected to be a routine first ultrasound.
Diagnosis is made by transvaginal ultrasound. The key finding is a gestational sac without a visible embryo (or yolk sac). Current guidelines from the Society of Radiologists in Ultrasound recommend that a definitive diagnosis be made only when the mean sac diameter is 25 mm or greater without a visible embryo.
If the sac is smaller than 25 mm, a follow-up ultrasound in 7 to 14 days is recommended. This is critical because very early normal pregnancies can look similar — the embryo may simply be too small to visualize yet. A repeat scan showing no growth confirms the diagnosis.
hCG levels in a blighted ovum may rise, plateau, or fall — the pattern varies. Because hCG is produced by placental tissue (which is present), levels can sometimes be in the thousands even without an embryo. This is why ultrasound, not hCG alone, is the diagnostic tool.
If you have experienced bleeding during pregnancy, an ultrasound to evaluate the pregnancy may lead to this diagnosis.
A blighted ovum is caused by chromosomal problems that occur at the very beginning of development — during the first few cell divisions after fertilization. The genetic code needed to form an embryo is absent, incomplete, or abnormal. The placental cells, which have a separate developmental pathway, may develop normally for a time.
This is entirely random. It is not caused by stress, exercise, diet, travel, sex, or anything else you did. It is not a sign that something is wrong with your fertility. Chromosomal errors in early pregnancy are extremely common — they are the cause of most first-trimester miscarriages.
Blighted ovum accounts for about 50 percent of first-trimester miscarriages, making it one of the most common reasons for early pregnancy loss.
Discuss all three options with your provider. Consider your emotional needs, timeline, and comfort level when making this decision. There is no medically superior choice.
If a blighted ovum is suspected but the gestational sac is small (under 25 mm), ask for a follow-up ultrasound in 1 to 2 weeks before making any treatment decisions. An early pregnancy can sometimes look like a blighted ovum simply because it is too early to see the embryo. A repeat scan gives the pregnancy time to develop if it is going to, while avoiding misdiagnosis.
All three management options — waiting, medication, or D&C — are medically valid. There is no wrong choice. Consider your emotional needs, schedule, pain tolerance, and desire for closure when deciding. Some people want the process to happen naturally; others want it over quickly. Your provider can help you weigh the pros and cons for your situation.
A blighted ovum is a pregnancy loss, and your feelings matter. You may have seen a positive test, told people, started imagining your future with this baby. Losing that is painful. Do not let anyone minimize your loss because 'there was never really a baby.' You were pregnant, you had hopes and plans, and this is a real loss.
Most people who experience a blighted ovum go on to have healthy pregnancies. A blighted ovum does not indicate a fertility problem or a recurring issue. It is a random chromosomal event. When you are ready, you can try again with confidence.
Your provider is there for both the medical and emotional aspects of this experience. Do not hesitate to reach out.
These symptoms need immediate medical attention regardless of your management approach.
Most providers recommend waiting for one normal menstrual period before trying to conceive again. This allows the uterine lining to regenerate and makes dating the next pregnancy easier. Some providers recommend waiting two to three cycles.
The prognosis for future pregnancies after a blighted ovum is excellent. This type of loss does not indicate a pattern or an underlying fertility issue. It is one of those random, unlucky events that is far more common than most people realize.
When you are ready, our guide on pregnancy after miscarriage can help you navigate the emotional complexity of trying again. You may also find our guides on miscarriage signs and support, molar pregnancy, and high-risk pregnancy helpful.
This guide is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider with any questions about your pregnancy.
