Blighted Ovum: Symptoms, Causes and What Happens Next

A Pregnancy That Looked Normal, and Then Did Not

If you have been told that your pregnancy scan shows an empty sac, I am sorry. You may have had a positive test, morning sickness and all the usual early signs, and it can feel deeply confusing to be told that no baby is developing. This is called a blighted ovum, or an anembryonic pregnancy. It is a real pregnancy loss, it is common, and it is almost never anything you caused.

This article is for education only and does not replace medical care. If you have heavy bleeding, severe pain, fever, or feel unwell, contact your doctor or go to the nearest emergency department straight away.

What Is a Blighted Ovum?

After fertilisation, the developing ball of cells splits into an outer layer (which forms the gestational sac and placenta) and an inner cell mass (which becomes the embryo). In a blighted ovum, the fertilised egg implants and the sac grows, but the embryo does not develop, or stops developing so early that it cannot be seen.

Because the outer cells still produce the pregnancy hormone hCG, your body continues to "feel" pregnant: you may miss periods, have positive tests, nausea and breast tenderness for a while.

How it differs from other early losses

• Chemical pregnancy: loss very soon after implantation, often before a sac can be seen on ultrasound. See chemical pregnancy causes and next steps.
• Miscarriage with an embryo: an embryo forms and then stops developing.
• Blighted ovum: the sac develops, but the embryo does not.

Why Does It Happen?

Most anembryonic pregnancies are caused by a chromosomal abnormality in the fertilised egg, such as an extra or missing chromosome. Cells with an incorrect genetic blueprint cannot form an embryo. These errors are usually random events at the time of egg or sperm formation or the first cell divisions, and they are not usually inherited or likely to repeat.

The chance of chromosomal errors rises as a woman gets older. See age-related fertility decline. Sperm quality also plays a part.

It is not caused by exercise, travel, work, stress, lifting something heavy, sex or eating something in particular.

Symptoms

Early on, a blighted ovum can look exactly like a healthy pregnancy. Later you may notice:

• Pregnancy symptoms such as nausea or breast tenderness fading
• Spotting or bleeding that progresses from light to heavier, sometimes with clots
• Cramping in the lower abdomen or back
• Passing tissue

Many women have no symptoms at all and the diagnosis is made on a routine early scan. Light spotting can also occur in healthy pregnancies, so do not assume the worst, but do have any bleeding checked. Learn about how to reduce the risk of miscarriage in early pregnancy and the first trimester.

How It Is Diagnosed

Ultrasound

A transvaginal ultrasound gives the clearest view in early pregnancy. Guidelines suggest that a gestational sac with a mean diameter of about 25 mm or more and no embryo or yolk sac supports a diagnosis of anembryonic pregnancy. If the sac is smaller, or the dates are uncertain, doctors usually repeat the scan after about a week or more so that a viable pregnancy is not wrongly labelled as failed. This waiting can be very hard, but caution matters. Read about types of ultrasound in pregnancy.

hCG blood tests

In a healthy early pregnancy hCG typically rises steadily over a couple of days. In a blighted ovum it may rise slowly, plateau and then fall. A single value cannot make the diagnosis, but repeated tests help show a trend. See hCG levels in early pregnancy.

Management Options

There is no single right choice. Your options depend on your health, symptoms and preferences.

Expectant management

Waiting for your body to pass the tissue naturally under medical supervision. It may take days to a few weeks and can be unpredictable, but it avoids medicines and procedures.

Medical management

Medicines such as misoprostol, sometimes with mifepristone, are prescribed to help the uterus expel the tissue. This lets you plan the process and it is often completed at home under clear instructions. Do not use these medicines without medical supervision.

Surgical management

A D&C or suction evacuation may be advised if:

• Bleeding is heavy or you feel faint
• There are signs of infection, such as fever or foul-smelling discharge
• Tissue is retained after other management
• You prefer a quicker, controlled procedure
• You want the tissue tested for chromosomal abnormalities

Scarring of the uterine lining after a D&C is uncommon, but it can happen. See Asherman syndrome and uterine adhesions.

Coping With the Loss

Grief after an anembryonic pregnancy is real and valid, even if the pregnancy was early. Some things that help:

• Allow yourself to grieve, and try not to tell yourself it "wasn't a baby yet".
• Talk with your partner. You may grieve in different ways.
• Speak to a counsellor or a support group if the feelings are overwhelming. Read emotional wellbeing during fertility treatment.

When Can You Try Again?

Physically, the uterus and hormones return to baseline over a few weeks. Many doctors recommend allowing at least one or two normal periods, which makes future dating easier, although you can try again once you are physically and emotionally ready. There is no need to rush.

When you feel ready, you can support a healthy pregnancy by:

• Taking folic acid (commonly 400 micrograms daily) before conception
• Eating well, staying active, not smoking and limiting alcohol and caffeine
• Discussing your plans with your doctor. See the 3-month preconception checklist

Once pregnant, an early visit is sensible. See when to start prenatal care. If you have been trying without success, see not getting pregnant after one year.

When to Look for a Cause

One blighted ovum is usually a random event. See a specialist if you have had two or more pregnancy losses, or one loss together with other risk factors such as older age. Evaluation may include:

• Genetic testing of the tissue and, when suggested, chromosome tests in both partners
• Uterine cavity assessment with scans or hysteroscopy
• Hormone and thyroid tests, and screening for antiphospholipid syndrome. See thyroid and fertility
• Embryo genetic testing with IVF in selected couples. See PGT-A vs PGD vs PGS

Learn more about recurrent miscarriage causes and treatment and my recurrent miscarriage service.

Support When You Need It

I see many women and couples after early losses in my Chennai practice. My approach is to explain what has happened, to manage this loss safely, and to work out whether any tests are needed before you try again. If you would like to talk, book a consultation with Dr. Rukkayal Fathima.

Medical disclaimer: this article is general information and not a substitute for medical advice. Please seek prompt medical care if you have heavy bleeding, severe pain or fever.