Blighted ovum, now more commonly called an anembryonic pregnancy, is a type of early pregnancy loss in which a gestational sac develops inside the uterus, but an embryo does not develop normally or stops developing very early in pregnancy.
The pregnancy may initially produce a positive pregnancy test because the body can continue producing human chorionic gonadotropin (hCG), the hormone detected by pregnancy tests.
A blighted ovum can be emotionally difficult for anyone experiencing it. Importantly, it is usually not caused by something the person did or failed to do.
What Is a Blighted Ovum?
A blighted ovum is an early pregnancy in which a gestational sac develops but a developing embryo is not seen when it should be visible on ultrasound.
The medical term commonly used today is anembryonic pregnancy.
In a normal early pregnancy, the fertilized egg implants in the uterus and develops into a gestational sac, yolk sac and embryo. In an anembryonic pregnancy, development does not proceed normally.
Anembryonic pregnancy is considered a form of early pregnancy loss.
Why Does a Blighted Ovum Happen?
In many cases, the exact cause cannot be identified.
One of the most common explanations is an abnormal number or arrangement of chromosomes in the developing pregnancy. Chromosomes contain genetic information needed for normal development.
When significant chromosomal abnormalities occur, the pregnancy may stop developing very early.
According to the American College of Obstetricians and Gynecologists (ACOG), approximately half of early miscarriages are associated with chromosomal abnormalities.
Important: It Is Usually Not Your Fault
Anembryonic pregnancy is generally not caused by ordinary activities such as:
- Walking
- Working
- Normal physical activity
- Having sexual intercourse
- Missing a particular food
- Experiencing an ordinary stressful day
It is important not to blame yourself after an early pregnancy loss.
Symptoms of a Blighted Ovum
Some people initially have typical symptoms of pregnancy, such as:
- A missed menstrual period
- Positive pregnancy test
- Breast tenderness
- Nausea
- Fatigue
As the pregnancy stops developing, pregnancy symptoms may decrease.
Some people may experience:
- Vaginal spotting or bleeding
- Lower abdominal cramps
- Passage of pregnancy tissue
However, some people have no obvious symptoms and only discover the problem during an ultrasound examination.
Bleeding or cramping in early pregnancy does not automatically mean that a miscarriage has occurred. Other causes are possible, and proper medical evaluation is important.
How Is a Blighted Ovum Diagnosed?
Ultrasound is one of the most important investigations used to evaluate early pregnancy development.
During an ultrasound examination, the healthcare professional evaluates structures such as:
- Gestational sac
- Yolk sac
- Embryo
- Cardiac activity, when appropriate for the gestational age
- Location of the pregnancy
- Measurements of pregnancy structures
An ultrasound showing an empty gestational sac does not always immediately mean that the pregnancy is nonviable, particularly when the pregnancy is very early or the dates are uncertain.
For this reason, healthcare professionals use established ultrasound criteria and may recommend a repeat ultrasound after an appropriate interval when the findings are uncertain.
Why Can a Repeat Ultrasound Be Necessary?
Pregnancy dating is not always exact.
Ovulation may occur later than expected, and implantation can also occur at different times. Consequently, a pregnancy that appears “too small” based only on the last menstrual period may actually be earlier than expected.
Making a premature diagnosis can potentially result in an ongoing pregnancy being incorrectly classified as nonviable.
ACOG emphasizes the importance of sufficient diagnostic certainty before treatment is initiated. In some situations, repeat ultrasound examinations and/or serial β-hCG blood tests may be required.
Can a Pregnancy Test Still Be Positive With a Blighted Ovum?
Yes.
A pregnancy test detects hCG, not the presence of a normally developing embryo.
After implantation, pregnancy tissue can produce hCG. Therefore, a person may continue to have a positive pregnancy test even when the pregnancy is no longer developing normally.
This explains why a positive pregnancy test alone cannot confirm that an early pregnancy is developing normally.
Can hCG Levels Be Normal in a Blighted Ovum?
hCG levels can remain elevated because pregnancy tissue may continue producing the hormone.
A single hCG result usually cannot provide all the information needed to determine pregnancy viability.
Depending on the situation, healthcare professionals may use:
- Serial quantitative β-hCG measurements
- Ultrasound
- Clinical symptoms
- Pregnancy dating
- Physical examination
together to reach a diagnosis.
Blighted Ovum Ultrasound Findings
An ultrasound examination may show a gestational sac without a visible embryo.
However, an apparently empty gestational sac in a very early pregnancy does not automatically establish an anembryonic pregnancy.
The ultrasound findings must be interpreted according to established diagnostic criteria and the clinical circumstances.
When viability is uncertain, a repeat ultrasound may be recommended rather than making an immediate diagnosis.
This cautious approach is important because ultrasound findings can vary according to gestational age, equipment, imaging technique and the timing of the pregnancy.
Is a Blighted Ovum a Miscarriage?
Yes.
A blighted ovum is considered a form of early pregnancy loss because the pregnancy is not developing normally.
The term “blighted ovum” is an older term. Anembryonic pregnancy is now commonly used in medical discussions because it more accurately describes the condition.
How Is a Blighted Ovum Treated?
Once an anembryonic pregnancy has been definitively diagnosed, management depends on the person’s medical condition, preferences and the healthcare professional’s assessment.
The main approaches to early pregnancy loss are:
1. Expectant Management
Expectant management means allowing the body to pass the pregnancy tissue naturally without immediate medication or surgery.
This approach may take time and can involve bleeding and cramping.
2. Medical Management
Medication may be prescribed by a qualified healthcare professional to help the uterus expel the pregnancy tissue.
The choice of medication and appropriate regimen should be determined by a healthcare professional based on the individual’s circumstances.
3. Surgical Management
A healthcare professional may recommend a procedure to remove pregnancy tissue from the uterus.
Surgical treatment may be particularly appropriate when there is heavy bleeding, infection, certain medical complications, or when other management approaches are unsuccessful or unsuitable.
ACOG recognizes expectant, medical and surgical approaches as accepted options for appropriately selected cases of early pregnancy loss.
Can a Blighted Ovum Happen Again?
Having one early pregnancy loss does not necessarily mean that future pregnancies will be affected.
Many people go on to have healthy pregnancies after an early pregnancy loss.
A detailed investigation is not routinely required after a single early pregnancy loss. Further evaluation may be considered when losses occur repeatedly or when other clinical factors suggest an underlying problem.
Can You Get Pregnant Again After a Blighted Ovum?
Yes.
An anembryonic pregnancy does not automatically mean that a person will have difficulty becoming pregnant in the future.
The appropriate timing for trying to conceive again can depend on physical recovery, emotional readiness and individual medical circumstances. A healthcare professional can provide personalized advice.
When Should You Seek Urgent Medical Attention?
Anyone experiencing possible pregnancy loss should seek medical assessment, particularly if symptoms are concerning.
Urgent medical attention is important if there is:
- Heavy vaginal bleeding
- Severe or worsening abdominal pain
- Dizziness or fainting
- Fever
- Feeling very unwell
- Foul-smelling vaginal discharge
These symptoms can sometimes indicate complications that require prompt medical care.
Frequently Asked Questions About Blighted Ovum
Does a blighted ovum mean I can never have a baby?
No. One anembryonic pregnancy does not mean that you cannot have a successful pregnancy in the future.
Can stress cause a blighted ovum?
Ordinary day-to-day stress is not considered a typical direct cause of anembryonic pregnancy. Chromosomal abnormalities are an important cause of early pregnancy loss.
Can a blighted ovum be prevented?
Unfortunately, most cases cannot be prevented because the underlying cause is often a random chromosomal abnormality that occurs during early development.
General preconception health care and appropriate medical care during pregnancy can support overall reproductive health, but they cannot prevent every early pregnancy loss.
Can ultrasound detect a blighted ovum?
Ultrasound can identify findings consistent with an anembryonic pregnancy, but diagnosis should follow established criteria. If the pregnancy is too early or viability is uncertain, a repeat scan may be necessary.
Is a blighted ovum the same as an ectopic pregnancy?
No.
A blighted ovum is an early pregnancy loss involving an intrauterine pregnancy. An ectopic pregnancy occurs when a pregnancy develops outside the normal cavity of the uterus.
Because ectopic pregnancy can be dangerous, healthcare professionals must establish the location of an early pregnancy when clinically necessary.
Final Thoughts
A blighted ovum, or anembryonic pregnancy, is a type of early pregnancy loss in which a gestational sac develops but an embryo does not develop normally.
It can be distressing, but it is important to remember that an early pregnancy loss is usually not caused by something the person did.
Ultrasound plays an important role in diagnosis, but an apparently empty gestational sac in a very early pregnancy may require follow-up before a definitive diagnosis is made.
If you have a positive pregnancy test followed by bleeding, pain, or concerning ultrasound findings, consult a qualified healthcare professional for proper evaluation.
Medical Review
Reviewed by Scientist Shauibu Omoko, Founder, Omokos Diagnostics.
This article has been prepared for general health education and reviewed for clarity and general medical accuracy. Diagnosis and treatment decisions should be made by appropriately qualified healthcare professionals.
Disclaimer
The information provided in this article is for general educational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment.
Every pregnancy is different. An ultrasound finding, pregnancy test result, or symptom should be interpreted in the context of the individual’s clinical history and examination.
Do not start, stop, or change any medication or treatment based solely on information provided in this article. If you are pregnant or experiencing bleeding, abdominal pain, or other concerning symptoms, seek appropriate medical care.
References
- American College of Obstetricians and Gynecologists (ACOG). Early Pregnancy Loss.
- American College of Obstetricians and Gynecologists (ACOG). Early Pregnancy Loss – Frequently Asked Questions.
- Mayo Clinic. Blighted ovum: What causes it?
- American College of Obstetricians and Gynecologists. Early Pregnancy Loss Patient Education.
