Ectopic pregnancy

What is an ectopic pregnancy?#

During ovulation, an egg (ovum) is released from one of the ovaries. Conception occurs when the egg meets a sperm in the fallopian tube. Normally, the fertilized egg then moves down the fallopian tube and into the uterus (womb), where it implants in the uterine lining (endometrium).

An ectopic pregnancy is a pregnancy that develops outside the uterus, usually in one of the fallopian tubes. In almost all cases, the embryo dies, because the developing placenta cannot reach a rich blood supply and the fallopian tube is not large enough to support a growing embryo.

In around 15 per cent of cases, the tube ruptures, causing pain, internal bleeding and shock. This is a medical emergency that needs immediate surgery and, in some cases, a blood transfusion. In an emergency, call your local emergency number (for example 911 in the US and Canada, 112 across the EU and many countries, 999 in the UK, or 000 in Australia) for an ambulance or go immediately to the nearest hospital emergency department.

An ectopic pregnancy can also develop in the cervix (the entrance to the womb), the abdominal cavity or the ovary itself, but these cases are rare. About 5 in 1,000 pregnancies are ectopic.

Symptoms#

An ectopic pregnancy can first appear to be a normal pregnancy, and its symptoms can mimic miscarriage or other reproductive conditions, such as pelvic inflammatory disease (PID) or endometriosis. Symptoms can include:

• the usual signs of pregnancy, such as a missed period, morning sickness and breast tenderness
• pain in the lower abdomen
• pain in the lower back
• cramps on one side of the pelvis
• vaginal bleeding or spotting
• sudden and severe pain in the lower abdomen, if the fallopian tube ruptures

Causes and risk factors#

An ectopic pregnancy is caused by a fertilized egg being unable to move through the fallopian tube. This can happen because of a blockage in the tube, or because the tiny hairs that line the tube cannot sweep the egg towards the uterus.

Factors that can increase the risk of an ectopic pregnancy include:

• damage to the fallopian tube, for example from a ruptured appendix
• past infection with PID or salpingitis (inflammation of the fallopian tubes) and the scarring this causes
• defects of the fallopian tube
• endometriosis
• successful reversal of a tubal sterilization
• use of assisted reproductive technologies
• a previous ectopic pregnancy

Contraception and ectopic pregnancy#

Modern contraceptives do not increase the overall risk of ectopic pregnancy. However, in the rare event that a pregnancy occurs while using contraception, a proportion of those pregnancies are ectopic. As a rough guide, this includes around:

• 5 per cent in people using copper IUDs or progestogen-only pills (mini pills)
• 10 per cent in people using the contraceptive implant
• up to 50 per cent in people using hormone-releasing IUDs

If a pregnancy follows a failed tubal sterilization, there is also a higher chance it will be ectopic, though the exact percentage is unknown.

Because implants and IUDs are extremely effective and pregnancy is highly unlikely, these methods can still be used by people with a past history of ectopic pregnancy. The progestogen-only pill can also be considered. Anyone using these methods should be aware of the symptoms of ectopic pregnancy.

Diagnosis#

Around 15 per cent of ectopic pregnancies are diagnosed in the emergency department after the fallopian tube has ruptured. In most cases, however, an ectopic pregnancy can be diagnosed using a range of tests, some of which are standard in pregnancy care, including:

• pelvic examination
• blood tests
• ultrasound
• laparoscopy (‘keyhole’ surgery)

Treatment#

A ruptured fallopian tube is a medical emergency. Laparoscopic surgery is done to remove the embryo, and attempts are made to repair the fallopian tube. A blood transfusion may also be needed.

For a non-emergency ectopic pregnancy, medication is often successful, but sometimes surgery is still needed. Anyone thought to have, or found to have, an ectopic pregnancy needs careful observation.

Future pregnancies#

Most people who have had an ectopic pregnancy can become pregnant again, but they need careful follow-up because their risk of another ectopic pregnancy is higher. Screening and improvements in early pregnancy monitoring have considerably reduced deaths from ectopic pregnancy.

Those at high risk should be monitored closely during early pregnancy with blood tests and ultrasound. Tell your doctor if your medical history includes any known risk factors, and see your doctor immediately if you have unusual pregnancy symptoms such as cramping, pain or vaginal bleeding.

Reducing your risk#

Many ectopic pregnancies are caused by scarring of the fallopian tubes. Ways to help reduce the risk of fallopian tube damage include:

• avoiding STIs by always using a condom when there is any possible risk of infection
• treating any sexually transmissible infection (STI) promptly
• treating any pelvic infection promptly

In an emergency, call your local emergency number (for example 911 in the US and Canada, 112 across the EU and many countries, 999 in the UK, or 000 in Australia) for an ambulance or go immediately to your nearest hospital emergency department.

Key points#

• An ectopic pregnancy develops outside the uterus, usually in a fallopian tube.
• Its symptoms can mimic miscarriage or other reproductive disorders.
• Sudden, severe lower abdominal pain may mean the fallopian tube has ruptured – a medical emergency.
• It is caused by a fertilized egg being unable to move through the fallopian tube.
• People who use long-acting contraception should be aware of the symptoms of ectopic pregnancy.

Where to get help#