What Is a Blighted Ovum? Causes, Signs and Treatments Explained

What Is a Blighted Ovum?

A blighted ovum is a pregnancy in which a fertilised egg attaches to the wall of the uterus, but no embryo forms inside the pregnancy sac. Doctors also call this an anembryonic pregnancy, meaning "without an embryo." The pregnancy sac keeps growing for a short while, even though the embryo never develops inside it.

Conception and embryo development are two separate steps, and a blighted ovum shows why. Conception happens when a sperm fertilises an egg, which then divides and grows into an embryo inside a gestational sac. With a blighted ovum, the sac forms, but the cells meant to become the embryo stop dividing very early, often before they are visible on a scan. It is a form of early pregnancy loss, usually in the first eight to ten weeks.

How Does a Blighted Ovum Occur?

In a typical pregnancy, a fertilised egg implants in the uterine lining around six days after fertilisation and begins forming two structures: the embryo and the gestational sac around it. By five to six weeks, an ultrasound can usually detect a small embryo inside this sac.

With a blighted ovum, implantation happens normally, but the cells meant to organise into an embryo stop developing very early, while the sac keeps growing because the placental tissue around it stays active. This is also why pregnancy tests can still turn positive: the placenta produces a hormone called human chorionic gonadotropin, or hCG, which keeps rising for a while. This is why many women only discover a blighted ovum at a routine dating scan.

Causes of a Blighted Ovum

Many women's first thought is, ‘Did I do something wrong?’ The answer is almost always no. A blighted ovum is usually linked to problems with the chromosomes, the structures inside cells that carry genetic information, in the fertilised egg. It is not caused by exercise, work, stress, travelling or anything you ate or didn't eat during early pregnancy.

Chromosomal Abnormalities

According to StatPearls, published by the National Center for Biotechnology Information, chromosomal abnormalities such as extra or missing chromosomes are one of the leading causes of a blighted ovum. When chromosomes do not pair up correctly, the cells meant to form an embryo cannot develop properly, so growth stops in the first few weeks.

Problems During Fertilisation

Sometimes the issue begins during fertilisation itself. If the egg or sperm were of poor quality, or if cell division goes wrong in the first days, the embryo may fail to develop even though the sac keeps growing. This is usually a random, one-time event.

Poor Embryo Development

In some cases, an embryo begins forming but stops growing very early, before it is visible on ultrasound, a process closely linked to the same chromosomal issues. This is why a blighted ovum can be hard to tell from a very early pregnancy on a first scan.

Other Possible Contributing Factors

Sperm DNA fragmentation, damage to the genetic material in sperm, may contribute to some cases, particularly with repeated losses. Autoimmune and endocrine (hormone-related) conditions have also been linked to it recurring, though one blighted ovum does not usually point to these.

Risk Factors for a Blighted Ovum

A blighted ovum can happen to anyone who conceives, but a few factors raise the chance of it.

• Advanced maternal age: A study in the International Journal of Reproduction, Contraception, Obstetrics and Gynecology found blighted ovum prevalence rose with maternal age, especially after 35.
• Previous miscarriage: A history of earlier loss, including a previous blighted ovum, raises the chance of it happening again, largely due to shared chromosomal factors.
• Genetic factors: A parent carrying a balanced chromosomal rearrangement, where genetic material is reshuffled without being lost, can pass an unbalanced set of chromosomes to the embryo.
• Lifestyle and environmental factors: Smoking, high alcohol intake, and exposure to certain toxins are generally linked to a higher risk of early pregnancy loss.
• Underlying reproductive health conditions: Thyroid disorders and structural uterine issues can make it harder for a pregnancy to progress normally at first.

Signs and Symptoms of a Blighted Ovum

The blighted ovum symptoms you notice often overlap with a normal early pregnancy at first, which is part of what makes it disorienting.

Early Pregnancy Symptoms

In the earliest weeks, a blighted ovum can feel exactly like any other pregnancy: a missed period, a positive test, breast tenderness, nausea and fatigue, since the placental tissue keeps producing hCG even without an embryo present.

Symptoms of Pregnancy Loss

As the pregnancy stops progressing, symptoms of loss may follow: vaginal bleeding, spotting, lower abdominal cramping, and a fading of earlier pregnancy symptoms. Bleeding does not always mean a miscarriage is happening, but it is a reason to contact your doctor.

When Symptoms May Not Be Present

Not every blighted ovum causes noticeable symptoms. In a silent or missed miscarriage, there may be no bleeding or cramping at all, and it is usually found only during a routine ultrasound, one reason early scans matter even when you feel fine.

How Is a Blighted Ovum Diagnosed?

Diagnosis combines ultrasound imaging with blood tests, usually confirmed over more than one visit.

Ultrasound Examination

A transvaginal ultrasound, a small probe placed inside the vagina for a clearer view of the uterus, is the main tool used. It shows whether a gestational sac has formed and whether an embryo is visible inside it.

Gestational Sac Measurements

According to StatPearls, an intrauterine sac measuring 25 millimetres or more across, the mean sac diameter, without a visible embryo, generally confirms an anembryonic pregnancy.

Follow-Up Ultrasound

If the sac is smaller than this, or your dates are uncertain, your doctor will usually recommend a follow-up scan seven to fourteen days later, since early pregnancies can simply look less developed than expected.

Beta hCG Blood Tests

Blood tests measuring beta hCG can support the diagnosis. According to a clinical review on Medscape, hCG in a healthy early pregnancy typically rises by at least 53 per cent every two days. A slower rise, plateau, or fall points toward a pregnancy that is not progressing normally.

Confirming the Diagnosis

Doctors are usually cautious about confirming a blighted ovum, since an incorrect diagnosis has serious consequences. So, confirmation generally requires ultrasound findings to meet accepted criteria, sometimes alongside a repeat scan.

Treatment Options for a Blighted Ovum

There is no single right way to manage blighted ovum treatment. Your doctor will talk you through which option suits your situation and comfort with each approach.

Expectant Management (Natural Miscarriage)

This means waiting for your body to pass the pregnancy tissue on its own. It avoids medication and surgery, but timing is unpredictable, and bleeding can be heavy.

Medication Management

This uses a medicine called misoprostol to help the uterus contract and expel the tissue. It usually works within a few hours to a couple of days, though it causes cramping and heavy bleeding.

Dilation and Curettage (D&C)

A D&C is a minor procedure in which the doctor widens the cervix and removes the tissue by suction, usually under sedation. It offers the most immediate resolution and allows tissue testing for chromosomal abnormalities if needed, but carries small risks such as infection or, rarely, scarring.

Choosing the Right Treatment Option

The right choice depends on how far along the pregnancy is, how heavily you are bleeding, and what feels manageable to you. Some prefer the control of a scheduled procedure, while others prefer to let the process happen naturally at home.

Recovery After a Blighted Ovum

Recovery happens on two tracks at once, physical and emotional, and both deserve attention.

Physical Recovery

Physical recovery is usually quick. Bleeding and cramping typically ease within one to two weeks, though it can take a little longer after a D&C. Mild fatigue and lower abdominal discomfort in the first few days generally improve on their own.

Emotional Recovery

Emotional recovery often takes longer than physical recovery. Even if the pregnancy ended very early, the loss is real, and there is no right or wrong way to feel. You may experience sadness, anger, guilt, relief or a mix of emotions. Giving yourself time to process the experience and talking to a partner, friend or counsellor experienced in pregnancy loss can make recovery easier.

When Menstrual Cycles Return

Most women get their next period within four to six weeks, depending on the treatment method and how quickly hCG levels return to zero. The first cycle after a loss may be slightly heavier or arrive earlier or later than usual.

Follow-Up Care

Your doctor will usually recommend a follow-up visit to confirm hCG levels have returned to normal and the uterus has healed, particularly after medication management or a D&C. This is also a good time to ask questions about future pregnancy planning.

Can a Blighted Ovum Affect Future Fertility?

Many people worry that a blighted ovum means they won't be able to conceive again. Thankfully, for most women, a blighted ovum is an isolated event and does not reduce the chances of having a healthy pregnancy in the future.

A single blighted ovum does not typically affect your underlying reproductive health. It is generally an isolated, one-time event caused by a chromosomal error, not a sign of an ongoing problem, and most women who experience one go on to carry a healthy pregnancy to term.

The risk of recurrence stays relatively low after one occurrence, though it can rise slightly with each additional loss. Afertility evaluation is usually only recommended after two or more consecutive losses, not after a single blighted ovum.

Pregnancy After a Blighted Ovum

Many women feel ready to try again soon, and for most, there is no medical reason to wait very long. Pregnancy after a blighted ovum is possible for the large majority of women once the body has recovered.

When Can You Try to Conceive Again?

Most doctors agree it is safe to try again once you have had at least one normal menstrual cycle after treatment, mainly to make dating a future pregnancy easier.

Steps to Prepare for a Healthy Pregnancy

It helps to make sure chronic conditions, such as thyroid problems or diabetes, are well managed. A balanced diet, moderate activity, and reducing alcohol and tobacco use all support a healthy pregnancy, though they do not guarantee against another loss.

Importance of Preconception Care

A preconception visit lets your doctor review your overall health and start you on a prenatal vitamin containing folic acid, which supports early foetal development, whether or not you have had a previous loss.

Early Pregnancy Monitoring

Once you conceive again, your doctor may suggest an earlier first ultrasound, around six to seven weeks, simply for reassurance. This closer monitoring is common after any earlier pregnancy loss.

Can a Blighted Ovum Be Prevented?

It is natural to want to know how to prevent this from happening again, though the honest answer is that, in most cases, a blighted ovum cannot be prevented. Since it is usually caused by a random chromosomal error at fertilisation, there is generally no action that could have stopped it. General habits still support a healthy pregnancy, including a healthy body weight, a balanced diet, avoiding smoking and excess alcohol, and managing conditions such as thyroid disorders or diabetes before conceiving.

If you have a health condition linked to pregnancy loss, managing it with your doctor before you conceive is one of the more meaningful steps you can take, and starting prenatal care early means any concerns can be picked up sooner.

When Should You Consult a Doctor?

A few symptoms and situations are worth calling your doctor about without waiting.

• Any bleeding during pregnancy, even light spotting
• Severe pain, or soaking through more than one pad an hour
• Recurrent pregnancy loss, meaning two or more consecutive early losses
• Ongoing concerns about future fertility
• Delayed recovery, such as bleeding beyond two weeks or no period within eight weeks of treatment

Conclusion

A blighted ovum can be an emotionally difficult experience, especially after the excitement of a positive pregnancy test. While it's natural to wonder if something could have been done differently, the reality is that this type of early pregnancy loss is usually caused by a random chromosomal change and is not your fault. With the right medical care and time to heal, most women recover well and go on to have healthy pregnancies. If you're feeling uncertain or overwhelmed, don't hesitate to speak with your doctor. They can guide you through both your recovery and your next steps when you're ready.