In a normal pregnancy, an egg is fertilised by sperm in one of the fallopian tubes, which connect the ovaries to the womb. The fertilised egg then moves into the womb and implants itself in the womb lining (endometrium), where it grows and develops. An ectopic pregnancy occurs when a fertilised egg implants itself outside the womb.

An ectopic pregnancy most commonly occurs in a fallopian tube (this is known as a tubal pregnancy). Ectopic pregnancies can also occur in an ovary, in the abdominal space or in the cervix (neck of the womb).

How common is it?

One pregnancy in 80 is ectopic in the UK. Records show there are 11,000 ectopic pregnancies in the UK each year, but this is thought to be an underestimate.

Outlook

The baby cannot be saved in a tubal ectopic pregnancy. However, with early diagnosis, the pregnancy can be safely ended using medication or surgery, without complications occurring (see Ectopic pregnancy - treatment for more information). Early diagnosis and treatment may improve the chances of having a normal pregnancy at a later date.

If left untreated, an ectopic pregnancy can be fatal. The fallopian tube can split (rupture), causing internal abdominal bleeding and life-threatening blood loss. Approximately five women a year die from an ectopic pregnancy in the UK.

Glossary

Ectopic

Ectopic refers to a pregnancy that occurs outside of the womb, most commonly in the fallopian tubes.

Fallopian tube

Fallopian tubes (also called oviducts or uterine tubes) are the two tubes that connect the uterus to the ovaries in the female reproductive system.

Ovaries

Ovaries are the pair of reproductive organs that produce eggs and sex hormones in females.

Cervix

The cervix is at the lower end of the womb. It connects the womb with the vagina.

Rupture

A rupture is a break or tear in an organ or tissue.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Many women who have an ectopic pregnancy do not experience any symptoms. The pregnancy may not be found to be ectopic until an early scan shows up the problem or a woman’s fallopian tube has ruptured (see below).

If there are symptoms, they usually appear between weeks 5 and 14 of the pregnancy. They are outlined below.

One-sided abdominal pain

You may experience pain on one side of your abdomen (tummy), which can be persistent and severe.

Vaginal bleeding

Vaginal bleeding is a different type of bleeding from your regular period. It often starts and stops, and can be bright or dark red in colour. Some women mistake this bleeding for a regular period and do not realise they are pregnant.

Shoulder tip pain

Shoulder tip pain is felt where your shoulder ends and your arm begins. It is not known exactly why shoulder tip pain occurs, but it usually occurs when you are lying down and is a sign that the ectopic pregnancy is causing internal bleeding.

The bleeding is thought to irritate the phrenic nerve, which is found in your diaphragm (the muscle used during breathing that separates your chest cavity from your abdomen). The irritation to the phrenic nerve causes referred pain (pain that is felt elsewhere) in the shoulder blade.

Bowel pain

You may experience pain when passing urine or stools (faeces).

Diarrhoea and vomiting

Ectopic pregnancies can cause similar symptoms to a gastrointestinal disease and are often associated with diarrhoea and vomiting.

Collapse

The most serious symptom of an ectopic pregnancy is known as 'collapse'. This occurs when an ectopic pregnancy has ruptured the fallopian tubes and is causing dangerous internal bleeding.

People who have experienced collapse describe feeling light-headed and faint, often accompanied by a feeling of 'something being very wrong'. You may also:

• feel sick
• have an increased heart rate
• look pale
• have diarrhoea

If your fallopian tubes rupture, you will need emergency surgery to prevent blood loss. In rare cases, a ruptured fallopian tube can be fatal, but in most cases the fallopian tube can be successfully repaired or removed.

In the early stages of pregnancy, an egg is released from one of your ovaries into one of your fallopian tubes, where it is fertilised by sperm.

Each fallopian tube is about 10cm (4 inches) long and lined with millions of moving hair-like structures called cilia. In a normal pregnancy the cilia push the fertilised egg along the tube and into the womb, where the egg implants itself into the lining of the womb (endometrium) and develops into a baby.

However, if the fallopian tube has been damaged, for example, if there is a blockage or narrowing in the tube, the cilia may not be able to move the egg to the womb and the pregnancy may develop in the fallopian tube.

There are many factors that increase the likelihood of having an ectopic pregnancy, such as:

• Previous ectopic pregnancy.
• Older age.
• Inflammation or infection. Most women who have ectopic pregnancies have had inflammation of the fallopian tubes (salpingitis) or an infection in the womb, fallopian tubes or ovaries (known as pelvic inflammatory disease). Also, endometriosis (where small pieces of womb lining are found outside the womb) can affect the fallopian tubes and cause an ectopic pregnancy.
• Fertility medicine. Taking medication to stimulate ovulation (the release of an egg) can increase the risk of ectopic pregnancy.
• Structural problems. Ectopic pregnancy is more likely if you have an abnormally shaped fallopian tube. This may be natural, or a result of previous surgery on the fallopian tubes that has caused scarring.
• Contraception. When used properly, pregnancy rarely occurs when taking the mini-pill and intrauterine device (IUD). However, in the rare cases when pregnancy does occur, it is more likely to be ectopic.

However, many women who have an ectopic pregnancy do not have any of the above risk factors and the cause is unknown.

Vaginal ultrasound

A transvaginal (through the vagina) ultrasound scan is sometimes used to diagnose an ectopic pregnancy. A small probe is inserted into your vagina to take a close-up image of your womb and surrounding areas. It will usually show the location of your pregnancy.

Blood tests

If you start to have symptoms of an ectopic pregnancy a few weeks into your pregnancy, you may be offered a blood test to measure blood levels of the hormone human chorionic gonadotropin (hCG), which is produced by placental tissue. The hCG levels are usually lower than normal if your pregnancy is ectopic or you are due to have a miscarriage.

Laparoscopy

If a diagnosis of ectopic pregnancy has still not been confirmed, a laparoscopy may be performed. This is a direct examination of the womb and fallopian tubes using a viewing tube (a laparoscope), which is passed through a small opening in the wall of your abdomen. The procedure is done under general anaesthetic (you are put to sleep).

Glossary

Scan

Ultrasound scans are a way of producing pictures of inside the body using sound waves.

The baby cannot be saved in an ectopic pregnancy. However, if the ectopic pregnancy is diagnosed before your fallopian tube ruptures, the pregnancy can be safely ended using medication or surgery. Your specialist, or gynaecologist, will be able to advise you about the benefits and risks of each option.

Surgery

Surgery to remove the embryo and placental tissue is the most common treatment for an ectopic pregnancy. Keyhole surgery is normally used. This is where a tiny camera and surgical instruments are inserted through small incisions (cuts) in your abdomen. If your fallopian tube has been damaged, it may also need to be removed (this procedure is called a salpingectomy).

To avoid having two surgical procedures, surgery to remove an embryo or fallopian tube is sometimes done at the same time as a laparoscopy to confirm your ectopic pregnancy. Your consultant will explain the chances of this happening to you before you go into hospital and get your consent to remove your fallopian tubes, if this is found to be necessary.

Medication

If an ectopic pregnancy is diagnosed early enough, it can be ended using a medicine called methotrexate. Methotrexate works by stopping the growth of the embryo cells. However, it can often cause side effects, such as abdominal pain, conjunctivitis and an upset stomach.

If methotrexate is recommended for you, your condition will need to be closely monitored through regular blood tests after you have taken the medicine. Methotrexate is given as an injection.

You need to use reliable contraception for three months after taking methotrexate as there is an increased risk of development problems in your next baby if you become pregnant after being given the medication.

There is still a 7% chance of having a ruptured ectopic pregnancy (when your fallopian tube splits) after medical treatment with methotrexate even if your hCG levels are going down.

Expectancy ('wait and see')

If your symptoms are mild, or you have no symptoms at all, your specialist may recommend delaying treatment to see how the ectopic pregnancy develops. Many embryos in an ectopic pregnancy die without the need for medical intervention to end the pregnancy. However, you will require frequent blood tests and close observation to monitor how the pregnancy is progressing.

Emergency surgery

If your fallopian tube has ruptured, you will need emergency surgery. The surgeon will make an incision in your abdomen (a laparotomy) to stop the bleeding and repair your fallopian tube. Often, the fallopian tube cannot be repaired and has to be removed (this is called a salpingectomy).

To avoid complications, it is important that an ectopic pregnancy is diagnosed as early as possible.

The later an ectopic pregnancy is diagnosed and treated, the more likely it is that your fallopian tubes will be damaged, leading to an increased likelihood of having another ectopic pregnancy in the future. You will also be at a higher risk of a ruptured ectopic pregnancy (when the fallopian tube splits) and severe internal bleeding, which can lead to shock (when your blood pressure suddenly drops to a dangerously low level) and, in an extremely small number of cases, death.

In the UK, many women who have an ectopic pregnancy receive early diagnosis and treatment. As many as 60% of women who have had an ectopic pregnancy conceive naturally afterwards.

Coping with pregnancy loss

Many women who have an ectopic pregnancy find the experience hard to deal with. You may feel depressed or sad, and you may also worry about your chances of having a healthy pregnancy in the future.

Counselling helps some couples come to terms with the loss of a pregnancy and the feelings of sadness, anger and guilt it can sometimes cause. Speak to your GP if you would like to be referred for counselling.

In-vitro fertilisation (IVF)

If both of your fallopian tubes are damaged or removed after an ectopic pregnancy, you may want to consider having in-vitro fertilisation (IVF) treatment to help you have a baby. IVF treatment is where an egg is fertilised by a sperm outside the womb (usually in a test tube) and, after fertilisation, the embryo is surgically implanted into the womb.

For more information, go to the Health A-Z topic on IVF.

There is nothing you can do to prevent an ectopic pregnancy from occurring, but you can protect yourself against pelvic inflammatory disease (PID), which can increase your likelihood of having an ectopic pregnancy.

PID can damage your fallopian tubes, increasing the risk of ectopic pregnancy. PID is usually caused by a sexually transmitted infection (STI), such as chlamydia or gonorrhoea, that starts in the vagina and spreads to the reproductive organs higher up.

The male condom is the most effective method of preventing STIs. It is also important to have regular sexual health check-ups:

• when you start a relationship with a new partner
• after having unprotected sex
• after having sexual contact with someone who you think may have been infected with an STI
• if you experience any symptoms of an STI

You can have a sexual health check-up by visiting your local genito-urinary medicine (GUM) or sexual health clinic. To find your local clinic see the NHS Choices service directory.

For more information, see the Health A-Z topic on pelvic inflammatory disease.