Molar pregnancy

Also called Hydatidiform mole, Gestational trophoblastic disease

A pregnancy that never develops normally, and a small number become cancerous. Follow-up is a national programme, and completing it matters.

What it is

A rare complication in which the tissue that would have formed the placenta grows abnormally, and the pregnancy cannot develop.

A complete mole has no fetal tissue at all; a partial mole has some, but it cannot survive.

It is uncommon, affecting roughly 1 in 600 pregnancies in the UK, and is more likely at the extremes of reproductive age.

**In a small proportion, the abnormal tissue persists or becomes cancerous**, called gestational trophoblastic neoplasia. That is why every molar pregnancy is registered with one of three national screening centres, in Sheffield, London and Dundee, and followed with regular urine or blood hCG measurements until the level normalises and stays normal.

**Completing that follow-up is the single most important thing**, and it is what turns a condition that could be dangerous into one that is almost always cured. Persistent disease responds extremely well to chemotherapy, with cure rates approaching 100 per cent when caught through surveillance.

Pregnancy must be avoided during follow-up, because a new pregnancy makes the hCG monitoring uninterpretable. The period varies and is set by the centre.

Emotionally it is a bereavement that is also a cancer risk, and both parts deserve acknowledging; women describe having to grieve a pregnancy while attending oncology follow-up.

Signs you might notice

Vaginal bleeding in early pregnancy, sometimes with grape-like tissue passed.

A womb larger than expected for the dates.

Severe nausea and vomiting, worse than usual.

Symptoms of an overactive thyroid: tremor, palpitations, sweating and heat intolerance.

Early pre-eclampsia, before 20 weeks, which is unusual and suggestive.

Often found at the first ultrasound, with a characteristic appearance and no fetal heartbeat.

Urgent: heavy bleeding, severe pain, or breathlessness, which can occur with spread to the lungs.

After treatment: any new bleeding, breathlessness, coughing blood, or a rising hCG, which needs urgent contact with the screening centre.

How it can affect day-to-day life

The dual nature is the hardest part. It is a lost pregnancy, and it is also a condition requiring cancer surveillance, and services often address only one of those.

The follow-up period, months of tests and no pregnancy, is a difficult wait, particularly for women who were trying to conceive. Knowing that most women go on to have normal pregnancies afterwards is genuinely reassuring and true.

Contraception is needed during follow-up, and the type should be discussed with the screening centre; barrier methods and the pill are generally used, and an intrauterine device is usually avoided until hCG has normalised.

The recurrence risk in a future pregnancy is around 1 in 80, so an early ultrasound is offered in subsequent pregnancies, and the products of any future miscarriage should be examined.

Where chemotherapy is needed it is usually well tolerated and highly effective.

Partners grieve too and are rarely asked about.

The specialist centres provide direct contact and are extremely experienced; women consistently rate that access highly.

Supporting someone well

Complete the follow-up. It is the whole of the safety net and it is what makes cure near-certain.

Register with the national screening centre and keep their contact details.

Avoid pregnancy for the period advised, and discuss contraception with the centre.

Report new bleeding, breathlessness or coughing blood promptly.

Ask for bereavement support; this is a pregnancy loss as well as a medical condition.

Ask the partner how they are.

Ask about the recurrence risk and about early scanning in a future pregnancy.

Have the tissue examined after any future miscarriage.

Ask for the centre's direct number and use it.

Where to get help

The early pregnancy assessment unit or gynaecology team initially.

One of the three national screening centres, in Sheffield, London and Dundee, which take over follow-up.

Miscarriage UK and Sands for bereavement support.

Macmillan Cancer Support on 0808 808 00 00 where chemotherapy is needed.