What is a blighted ovum? Causes, symptoms and treatment

What is a blighted ovum?

A blighted ovum happens when a fertilised egg attaches itself to the uterine wall, but the embryo does not develop. Cells develop to form the pregnancy sac, but not the embryo itself.

In normal cases, when a woman becomes pregnant, the fertilised egg attaches to the uterine wall. At about five to six weeks of pregnancy, an embryo should be present, together with the gestational sac.

With a blighted ovum, though, the pregnancy sac forms and grows, but the embryo does not develop. That’s why a blighted ovum is also called an anembryonic pregnancy.

A blighted ovum occurs early on, within the first trimester, even before the woman may have realised she is pregnant. It will cause a miscarriage usually at seven to 12 weeks of pregnancy. The body realises that the pregnancy is not developing properly and starts to shed blood and tissue from the uterus.

Pregnancy hormones are still produced in case of a blighted ovum, so it can show as a positive pregnancy test early on.

Anembryonic pregnancy causes

In a normal pregnancy, the egg starts dividing within hours after being fertilised. 

Around 10 days later, the cells will have formed an embryo, which will implant itself in the uterus. Then the placenta begins to develop and hormone levels begin to surge. 

With a blighted ovum, the cells never divide to the point of forming an embryo, or the embryo stops growing very shortly after it implants in the uterus.

Studies have revealed that an anembryonic pregnancy usually happens because of abnormal chromosomes in the foetus. This can be caused by abnormal cell division or poor quality of sperm or egg. The body terminates the pregnancy because the foetus will not develop into a healthy baby. 

It is important to understand that it was not your fault and there was nothing you could have done to prevent it from happening. For most women, a blighted ovum occurs only once. If you have repeated blighted ovum pregnancies, talk to your doctor about a chromosomal analysis of your embryos.

Blighted ovum symptoms

In many cases, a blighted ovum can occur very early in pregnancy before most women even know that they are pregnant.

A blighted ovum may have the same early symptoms associated with pregnancy, such as:

• A positive pregnancy test
• Breast tenderness
• Nausea and vomiting
• A missed period
• An ultrasound showed an amniotic sac but no embryo

As the pregnancy ends, symptoms may include miscarriage. These can include:

• Vaginal spotting or bleeding
• Abdominal cramping
• Disappearance of breast soreness
• A period that is heavier than usual.
• Blood clots or greyish tissue passing from the vagina

Anembryonic pregnancy – diagnosis and treatment

A blighted ovum is usually detected on the first ultrasound given during a prenatal appointment. Sometimes, there may have been bleeding at the start of the pregnancy and an ultrasound is used to investigate.

It will show the placenta and empty embryonic sac. In some cases, a transvaginal ultrasound, in which a wand is inserted directly into the vagina, may be used to confirm a blighted ovum if the results of a standard abdominal ultrasound are inconclusive.

In case of a blighted ovum, your doctor may suggest these treatment options:

• Waiting for miscarriage symptoms to occur naturally
• Taking medication to bring on a miscarriage
• Having a D&C (dilation and curettage) surgical procedure to remove the placental tissues from the uterus

Your doctor will discuss the options with you. You will want to discuss the side effects and the standard risks associated with any type of medication or surgical procedure, including a D&C.

You might choose to allow a natural miscarriage to happen. Once this starts, it can take days to weeks for the bleeding to finish. If the bleeding is getting heavier, if you are in pain or if you feel unwell, see your doctor. 

Your doctor also needs to monitor the process to ensure that all the tissue in the uterus has been appropriately expelled. If tissue remains in the uterus after the miscarriage, a D&C may still be required. If the tissue is not removed, an infection can occur and lead to a potentially serious complication called a septic miscarriage.

A D&C will also be helpful if you want a pathologist to examine tissues to confirm the reason for the miscarriage.

Risk factors of having a blighted ovum

Experts estimate that a third of early pregnancy loss, those before eight weeks of gestation, are due to blighted ovums. 

Some risk factors include:

• Chromosomal abnormalities
• History of miscarriage
• Being older than 35
• Obesity
• Infections such as toxoplasmosis, chlamydia, or syphilis
• Uterine abnormalities 
• Luteal phase defect
• Smoking
• Abuse of alcohol or drugs
• Diabetes and Thyroid diseases
• Exposure to toxins (for example, pesticides) and ionising radiation

ALSO READ: Do you know? The different types of miscarriages

How to cope with a blighted ovum

The loss of a pregnancy can be very hard. It is natural to feel upset, sad or even guilty. In case of a blighted ovum, remember that it wasn’t your fault, and there was no way that you could have prevented it.

Talking to family members, friends, a counsellor, or your doctor may help you cope with your loss.

Here are some things you need to take note of after a blighted ovum:

• You will probably have vaginal bleeding, similar to a heavy period, for up to a week. Use pads instead of tampons. You may use tampons during your next period, which should start in three to six weeks.
• You may have cramps for several days after the miscarriage. Over-the-counter pain medication such as acetaminophen or ibuprofen may help. Inform your doctor if you are experiencing any severe pain.
• Monitor your temperature in the evening for the next five days after the miscarriage. Call your doctor if you have a temperature above 100°F (37.7 degrees Celsius).
• Your doctor may want you to collect tissue that you might pass. Use a clear container for it and take it to your doctor as soon as you can.
• Avoid having sex until the bleeding stops. 
• It is also recommended that you avoid heavy exercise until the bleeding stops.
• If you plan to get pregnant again, check with your gynaecologist. Most doctors suggest waiting until you have had at least one normal period before you try to get pregnant again. If you do not want to get pregnant, ask your doctor about birth control.
• Eat a balanced diet that is high in iron and vitamin C. You may be low in iron because of blood loss. Talk to your doctor about whether you need to take iron pills or a multivitamin.

Can I get pregnant again after an anembryonic pregnancy?

Having a blighted ovum in pregnancy will not affect your chances of conceiving and having a successful pregnancy in the future. In a study of women with early miscarriages, including blighted ovums, around 80 per cent went on to give birth to a healthy baby within five years.

Will I have another blighted ovum pregnancy?

A blighted ovum is usually a one-time occurrence. However, in the rare case of repeated incidents of blighted ovum, your doctor may recommend testing to identify possible causes. 

ALSO READ: Egg freezing is banned in Singapore, but Freedom Edge is empowering women with options

Can it be prevented?

Unfortunately, in most cases, an anembryonic pregnancy cannot be prevented. In case of multiple early pregnancy losses, do talk to your doctor about possible genetic causes, and if any tests are required.

Most doctors recommend that couples wait for at least one to three regular menstrual cycles before trying to conceive again after any type of miscarriage so that their body has time to recuperate fully and is ready to support pregnancy. 

During this time, focus on healthy lifestyle habits for your body and mental health, such as:

• Eating well
• Sleeping well and keeping stress at bay
• Exercising
• Taking a daily prenatal supplement that contains folate

If you are experiencing any pregnancy symptoms or have any concerns about your reproductive health, do not hesitate to consult with a gynaecologist. 

This article was first published in theAsianparent.