17889 Molar Pregnancy

Overview

A molar pregnancy is a rare condition where abnormal tissue grows in the womb instead of a normal baby. It happens because of a problem with the chromosomes (the genetic material) when the egg is fertilised. The tissue forms a mass that looks like grapes under a microscope. It is not a baby and cannot survive.

No, molar pregnancy is rare. It happens in about 1 in every 1,000 pregnancies in the UK and similar rates in other countries.

Molar pregnancy affects women who are pregnant. It is more common in women under 16 or over 45, and slightly more common in certain ethnic groups, but it can happen to anyone.

Symptoms

Common symptoms

• Vaginal bleeding in early pregnancy, often dark brown or bright red
• Severe nausea and vomiting
• Pain or pressure in the pelvis
• A womb that grows faster than expected for the stage of pregnancy
• High blood pressure or protein in the urine (signs of pre-eclampsia)
• No fetal heartbeat or baby seen on ultrasound

Causes

Main causes

• A molar pregnancy is caused by errors in the chromosomes during fertilisation. In a complete molar pregnancy, the egg has no maternal genetic material, and only paternal chromosomes are present. In a partial molar pregnancy, the egg has one set of maternal chromosomes but two sets of paternal chromosomes.
• These chromosome errors cause abnormal tissue to grow rapidly instead of a normal embryo forming.

Risk factors

• Very young age (under 16) or older maternal age (over 45)
• A previous molar pregnancy (higher chance of another one)
• A history of miscarriage or previous pregnancy complications
• Some studies suggest a diet low in vitamin A or carotene may increase risk, but this is not fully proven.

When to see a doctor

See a doctor urgently if:

• If you are pregnant and have any vaginal bleeding, especially if it is heavy or accompanied by pain
• If you have severe nausea, vomiting, or signs of pre-eclampsia (headache, vision changes, swelling)
• If you have been diagnosed with a molar pregnancy and develop new symptoms like chest pain or a persistent cough

Book a routine appointment if:

• If you have had any unusual symptoms in early pregnancy and want them checked
• If you have had a molar pregnancy and need follow-up blood tests or appointments
• Before getting pregnant again after a molar pregnancy, to make sure your hormone levels have returned to normal

Diagnosis

A molar pregnancy is usually found during an ultrasound scan, sometimes at your routine early pregnancy scan. It can also be suspected after a miscarriage if you have unusual symptoms. A blood test to check your hCG (pregnancy hormone) level is also used.

Tests that may be done

• Ultrasound scan of the womb
• Blood test to measure hCG levels
• A sample of tissue (biopsy) taken after the molar tissue is removed
• Chest X-ray or other scans if there is a concern that the growth has spread outside the womb

What to expect at your appointment

Your doctor will explain the findings and talk to you about treatment. In most cases, you will need a short surgical procedure to remove the molar tissue. After that, you will have regular blood tests to monitor your hCG level until it returns to normal. This monitoring is very important and usually lasts for at least 6 months.

Treatment

Treatment for a molar pregnancy involves removing the abnormal tissue from your womb. After removal, you will have close follow-up to ensure that no abnormal cells remain or spread. Most women do not need any further treatment, but if the condition becomes persistent, chemotherapy may be needed.

Self-care at home

• Attend all follow-up appointments and blood tests as directed by your healthcare team
• Use a reliable contraceptive method to avoid pregnancy until your doctor says it is safe (usually 6 to 12 months)
• Take time to rest and recover, and seek emotional support from friends, family, or a counsellor
• Keep a healthy balanced diet and stay gently active as your recovery allows

Medical treatments

The first treatment is usually a minor surgical procedure called suction curettage, where the doctor gently removes the abnormal tissue from the womb using a thin suction device. This is done under general anaesthetic. If the hCG level does not fall normally after surgery, or if the molar tissue has spread, chemotherapy medicines may be used. Your specialist team will decide on the best treatment for you. Do not take any medicines for this condition without your doctor's advice.

When is surgery considered?

Surgery is the standard treatment for molar pregnancy. In rare cases, a hysterectomy (removal of the womb) may be recommended, especially for older women who do not wish to have more children, or if there is severe bleeding or cancer-like growth.

Living with this condition

After treatment, you will need regular blood tests until your hCG level is normal for several months. This monitoring may last 6 to 12 months. It is important not to become pregnant during this time, because pregnancy would raise your hCG level and make monitoring difficult.

Lifestyle tips

• Give yourself time to heal physically and emotionally.
• Talk openly with your partner, family, or friends about your feelings.
• Avoid alcohol and smoking, as they can affect recovery.
• Ask your doctor when it is safe to resume activities like exercise, driving, and work.

Diet and exercise

Eat a balanced diet with plenty of fruits, vegetables, and lean proteins. Light exercise like walking is usually fine once your doctor agrees, but avoid heavy lifting or intense workouts until you have fully recovered.

Mental health and emotional wellbeing

A molar pregnancy can be a very distressing experience. You might feel grief, shock, worry, or even guilt. These feelings are completely normal. It is important to talk about them. If you are feeling very low, anxious, or hopeless, speak to your GP or healthcare team. They can refer you to counselling services. If you ever have thoughts of harming yourself, reach out for help immediately.

Prevention

There is no known way to prevent a molar pregnancy. Most cases happen randomly due to chromosome errors in the egg or sperm. You cannot predict or avoid it.

Complications

If left untreated

• If left untreated, a molar pregnancy can cause heavy, persistent bleeding that may lead to anaemia or low blood pressure.
• The abnormal tissue may continue to grow within the womb and can cause infection or damage to the womb lining.
• In some cases, the molar tissue can spread to other parts of the body, such as the lungs, forming a type of cancer called gestational trophoblastic neoplasia (GTN).

Long-term outlook

The outlook is very good. Nearly all women are cured with treatment, and the chance of the condition becoming cancer is low (around 15% for complete and 1% for partial molar pregnancy). Even if it does become cancer, it is usually highly treatable with chemotherapy. Most women who have had a molar pregnancy can go on to have successful, healthy pregnancies in the future, although they may need extra monitoring early in the next pregnancy.

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