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Management of Molar pregnancy (Hydatidiform Mole)

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Molar pregnancies are unusual, and it is likely that you have not heard of them before. We are sorry that your pregnancy will not continue as you had expected, and you are likely to feel sad and anxious. You will have lots of questions about this condition, and the shock of your diagnosis can make it difficult to understand and remember everything the doctors and nurses talked about at the time. This information leaflet aims to answer some of your questions.

What is a Hydatidiform Mole?

A hydatidiform mole, or molar pregnancy, is a medical term which means fluid filled mass of cells. The cells that normally become the placenta grow too quickly and fill the womb where the embryo would normally develop. This means a normal pregnancy cannot develop. These cells are called trophoblasts. It happens because there is a problem with the mixing of genetic material from the sperm and egg when they join together at fertilisation. It is a rare condition, occurring in about 1 in 600 pregnancies.

There are 2 different types of molar pregnancy: complete or partial hydatidiform mole. Very occasionally the molar tissue persists or spreads to other parts of the body, forming a choriocarcinoma.

This is extremely rare and needs to be treated and followed up very carefully, as it is a form of cancer. It is very important that you understand that this process is not a termination of pregnancy (an abortion). In most cases there never was an embryo or it died at a very early stage, and even in a partial mole it will not develop. Even so, you may still feel a sense if loss for what would have been your baby.

Will I experience any symptoms?

You may have experienced symptoms which you will have attributed to pregnancy. This is because the hormones released from the trophoblast cells of the molar pregnancy are the same type that is produced during a normal pregnancy. However, in a mole, the level of pregnancy hormones released tends to be much higher.

  • You will have missed periods.
  • You may have been feeling very nauseous or troubled by severe vomiting.
  • There may have been some vaginal bleeding, which can contain tiny watery sacs.
  • You may have had very heavy bleeding, and have been worried about miscarrying.

How will I be treated?

An ultrasound scan and hormone blood tests will be performed to confirm the diagnosis of a mole.

You will then be admitted to hospital to have a short operation. The method of surgically managing a miscarriage is called a SMM. We use a gentle suction device to remove the remaining pregnancy tissue from the inside of the womb. It is normally performed under a general anaesthetic (you will be asleep) this operation can be arranged as a day case at either Lewes Victoria Hospital, The Royal Sussex County Hospital or Princess Royal Hospital and will depend on availability. The surgery takes between 5-10 minutes. You will usually be able to go home 3-4 hours after your procedure. A very rare complication that may occur during the operation is that we go through the wall of the womb with the instruments we use known as perforation of the womb. The risk is low, occurring in 1 in 1000 cases. If this occurs we would need to look inside your abdomen with a telescope. It is unlikely that you would need anything more than close watching for a few days after surgery.

Because there is also a risk of infection following an SMM (one in ten cases) any lower stomach pains, offensive discharge or fever should be investigated by your GP and antibiotics prescribed if necessary.

What can I expect after the procedure?

You may experience episodes of pain or nausea after a general anaesthetic. This is common, and the nursing staff can give you medication to help.

Before you go home you need to have had something to eat, mobility checked and passed urine. You will need to be collected from hospital by a responsible adult in a car or taxi, as you can not drive for 24 hours after an anaesthetic, or make any important decisions. You also need to have an adult with you for the following 24 hours.

The anaesthetic is short-lasting. You should not have or suffer from any side effects for more than a day after the procedure. You may experience some mild period type cramps and bleeding.

The bleeding is usually light and should settle within two weeks. However if bleeding is heavy or persists for more than three weeks then you should visit your GP as this may indicate that some tissue remains. If this bleeding does not settle with a course of oral antibiotics, it is sometimes necessary to have a second SMM (two in1000 cases). To reduce the risk of infection you should use sanitary towels rather than tampons.

What follow up is required and why is this necessary?

The pregnancy tissue removed during surgery is sent to the lab and the results usually take 6 weeks from date of surgery to be confirmed by the Histopathologist. We then will arrange for you to be seen by the consultant.

It is important that you are then registered with one of three centres in the UK who specialise in molar pregnancies. Very occasionally molar pregnancy can continue to grow even after the operation. They will follow you with a series of blood and urine tests over a period of 6-12 months, to ensure that none of the molar pregnancy remains.

If your pregnancy hormone levels fail to drop, or start to increase, you will be referred for further treatment.

Can I get pregnant again?

A molar pregnancy does not affect your fertility in any way. However, it is not recommended to try for a baby during your follow up period. During this time, we would also ask you to use contraceptives other than the pill, as the hormones within the tablets can cause any remaining molar tissue to grow. There are various other methods of contraception, and your GP or local family planning clinic would be happy to advise you.

Contact details and further sources of information and advice

Royal Sussex County Hospital
Main: 01273 696955
EPAC: 664402, Monday to Friday 8 to 4
Level 11: 523191

Princess Royal Hospital
Main: 01444 441881
EPAC: extension 8370 or extension 5686
Horsted Keynes: extension 5685

Hydatidiform Mole and Choriocarcinoma UK information and support service

If you have bleeding and /or pain you can get medical help and advice from:

  • Your GP or midwife who may advise you to go to hospital.
  • Your nearest EPU which can be found at
  • Referral into the Early pregnancy unit is based on assessment by a health professional.

NHS CHOICES 111 when you need medical help fast but it’s not a 999 emergency. The service is available 24 hours a day, 365 days a year. Calls are free from landlines and mobile phones.

The Miscarriage Association
17 Wentworth Terrace
Tel: 01924 200799

This is an organisation through which you may find information and support that you need to help you through if you have been affected by miscarriage.

  • BSUH NHS TRUST(2011) GP001 Early Pregnancy Unit Clinical Guidelines.
  • Patient UK Information leaflets Women’s Health Category.
  • Royal College of Obstetricians and Gynaecologists
  • National institute for Heath and Clinical Excellence: Clinical Guidelines: Nice Pathways

This information is intended for patients receiving care in Brighton & Hove or Haywards Heath.

The information here is for guidance purposes only and is in no way intended to replace professional clinical advice by a qualified practitioner.

Publication Date: April 2021

Review Date: January 2024

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