ConditionWomen's & pregnancy health
Blighted Ovum (Anembryonic Pregnancy)
A blighted ovum, or anembryonic pregnancy, is an early pregnancy in which a gestational sac forms in the uterus but no embryo develops inside it. It is a common cause of early miscarriage, usually caused by chromosome problems in the fertilized egg, and is not caused by anything the pregnant person did. Pregnancy tests stay positive and you may feel pregnant, so it is often found on an ultrasound. Options include waiting, medicine or a minor procedure, and most people go on to have healthy pregnancies.
Also called: Anembryonic pregnancy, anembryonic gestation, empty sac
At a glance
- What it is
- An early pregnancy with a gestational sac but no embryo.
- Why it happens
- Usually chromosome abnormalities at conception. Not caused by exercise, stress or sex.
- Signs
- Often none. Some have spotting, cramping or fading pregnancy symptoms.
- Diagnosis
- Transvaginal ultrasound, sometimes repeated 1 to 2 weeks later.
- Treatment
- Waiting for natural miscarriage, misoprostol (often with mifepristone), or uterine aspiration.
When to get help
Call 911 or go to the ER
- Heavy bleeding soaking 2 or more pads an hour for 2 hours in a row, or passing large clots with dizziness or fainting
- Severe one-sided pelvic pain, shoulder-tip pain or fainting in early pregnancy (rule out ectopic pregnancy)
See a doctor within a day or two
- Fever above 38 °C (100.4 °F), chills or foul-smelling discharge after miscarriage or treatment (possible infection)
- Severe cramping not relieved by pain medicine
- Bleeding that continues heavily more than 2 weeks after treatment
Book a routine appointment
- Spotting or mild cramping in early pregnancy: contact your provider to arrange assessment
- Pregnancy symptoms that suddenly fade in the first trimester
- Questions about trying again or about two or more previous losses
What a blighted ovum is
After fertilization, the egg divides and implants in the uterus. Cells develop into both the gestational sac and placenta and into the embryo. In a blighted ovum, the sac and early placental tissue develop, but the embryo stops developing very early or never forms. The placental tissue keeps producing the pregnancy hormone hCG for a while, so pregnancy tests remain positive.
It is one of the most common types of early pregnancy loss, or miscarriage. Early pregnancy loss overall happens in roughly 10 percent of known pregnancies.
Causes
The main cause is a chromosomal abnormality in the fertilized egg, usually a random error in how the egg or sperm divided. This is not inherited and is unlikely to recur.
Things that do not cause a blighted ovum:
- exercise or work
- sex
- stress
- minor falls
- morning sickness medicines
The risk of early loss rises with the age of the egg, especially after 35.
Signs and symptoms
Many people have no symptoms and feel pregnant until the ultrasound. Possible signs include:
- light spotting or brown discharge (see bleeding during pregnancy)
- mild cramping or pelvic pain
- pregnancy symptoms, such as nausea and breast tenderness, fading
- later, vaginal bleeding and cramping as the body begins to miscarry
Diagnosis
A transvaginal ultrasound (a probe placed in the vagina) gives the clearest view. Because a normal embryo can be too small to see very early, doctors follow strict criteria before diagnosing a nonviable pregnancy, to avoid any risk of ending a healthy pregnancy.
A blighted ovum is confirmed when:
- the gestational sac measures 25 mm or more in average diameter with no embryo, or
- no embryo with a heartbeat is seen 2 weeks or more after a scan showing a sac without a yolk sac, or
- no embryo with a heartbeat is seen 11 days or more after a scan showing a sac with a yolk sac
If the findings are suspicious but not definite, the scan is repeated 7 to 14 days later. Blood hCG levels may be measured, but ultrasound is the deciding test. If the location of the pregnancy is uncertain, ectopic pregnancy must be ruled out.
Treatment options
There are three safe options. The choice depends on your preference, your health and how quickly you want it resolved.
| Option | What happens | Pros | Cons |
|---|---|---|---|
| Expectant management | Wait for the body to pass the tissue naturally | No medicine or procedure | Can take days to weeks. Bleeding is unpredictable. May not complete |
| Medicine | Mifepristone followed by misoprostol (or misoprostol alone), taken by mouth or vaginally | Done at home, avoids a procedure | Cramping and heavy bleeding for hours. Sometimes a procedure is still needed |
| Uterine aspiration (D&C) | Tissue removed by gentle suction in a clinic or operating room | Quick and most predictable. Tissue can be tested | Small procedural risks, such as infection |
What to expect
- Bleeding is usually heavier than a period, with clots, and strong cramping, then tapers over 1 to 2 weeks.
- Pain relief: ibuprofen and acetaminophen (paracetamol) at the label dose, and heating pads.
- A follow-up visit, ultrasound or pregnancy test confirms the uterus is empty.
- If your blood type is Rh-negative, your provider may discuss an Rh immune globulin injection.
Physical and emotional recovery
Periods usually return within 4 to 6 weeks. Most people can resume normal activities within a few days. Avoid putting anything in the vagina for about 1 to 2 weeks, or as advised, to reduce infection risk.
A blighted ovum is a real pregnancy loss, and grief, sadness, anger and anxiety are normal. Partners grieve too. Support from family, friends, counselors or pregnancy loss groups can help. Talk to your provider if low mood persists or affects daily life.
Trying again
- You can usually try to conceive again once you feel ready. Many providers say there is no need to wait beyond one normal period.
- The chance of a healthy next pregnancy is high.
- Most people do not need tests after one loss. Testing is usually offered after two or three consecutive losses.
- Taking folic acid before conception is recommended for all future pregnancies.
Frequently asked questions
What are the signs of a blighted ovum?
Often there are none, and it is found on a routine early ultrasound. Some people notice spotting, mild cramping or fading pregnancy symptoms such as less nausea and breast tenderness. Pregnancy tests remain positive because the placental tissue still produces hormones.
Can an ultrasound be wrong about a blighted ovum?
Very early scans can miss an embryo that is simply too small to see. That is why doctors use strict size and timing criteria, and often repeat the scan 7 to 14 days later, before confirming the diagnosis. Once these criteria are met, the diagnosis is reliable.
What causes a blighted ovum?
Most are caused by random chromosome errors at conception, which stop the embryo from developing. They are not caused by stress, exercise, sex or anything you did. The risk rises with maternal age.
How long does it take to miscarry a blighted ovum naturally?
It varies. Some people miscarry within days, others take several weeks, and in some it does not complete without treatment. If you prefer not to wait, medicine or a uterine aspiration can resolve it sooner.
Can I have a healthy pregnancy after a blighted ovum?
Yes. Most people who have a blighted ovum go on to have a healthy pregnancy next time. A single early loss does not significantly increase the risk of future losses. Testing is usually recommended only after two or three losses in a row.
Sources
This guide was written from current patient and clinical guidance, including:
- American College of Obstetricians and Gynecologists: Early Pregnancy Loss (Practice Bulletin 200)
- Society of Radiologists in Ultrasound: Diagnostic criteria for nonviable pregnancy early in the first trimester (NEJM 2013)
- MedlinePlus: Miscarriage
- NHS: Miscarriage
- March of Dimes: Miscarriage