Patient information from BMJ

Ectopic pregnancy: what is it?

Last published:Sep 02, 2021

An ectopic pregnancy happens when a fertilised egg starts to develop in a part of a woman’s body other than the womb. Without treatment, ectopic pregnancy can be dangerous for the mother.

What is ectopic pregnancy?

In a healthy pregnancy an egg fertilised with sperm travels from the woman’s ovary, along one of her two fallopian tubes, to the womb (uterus) where it develops into a fetus. But sometimes the egg starts to develop in the wrong place, usually the fallopian tube.

The main danger of ectopic pregnancy is that, as the egg grows, it will rupture (break) the wall of the fallopian tube. This can cause internal bleeding that, in some cases, can be fatal for the woman.

It can be extremely distressing to have to end a pregnancy, especially if you have been trying to become pregnant. But an egg that starts to develop outside the womb cannot develop into a normal fetus and will not be able to live.

Sometimes this type of pregnancy will end by itself. But many women need drug treatment or surgery to end the pregnancy.

One or two in every 100 pregnancies are ectopic. Most ectopic pregnancies happen for no known reason. But some things can make them more likely. These include:

• having had a previous ectopic pregnancy

• having had an infection in the pelvis

• smoking

• using a type of contraceptive called an intrauterine device (IUD)

• having had a lot of different sexual partners in your life

• having previously had surgery on your fallopian tubes

• having had fertility problems before

• having previously had in vitro fertilisation (IVF) treatment

• being aged over 35

• having African-Caribbean ancestry. 

Another possible cause of ectopic pregnancy is having been exposed in the womb to a drug called diethylstilbestrol (DES). This is a drug that was given to pregnant women in some countries for some years up to the 1970s. For you to have been exposed, your mother must have taken this drug while pregnant with you.

What are the symptoms?

The most common symptoms of ectopic pregnancy are:

• abdominal (tummy) pain and tenderness

• not having had a menstrual period for a month or two

• unusual vaginal bleeding.

If your doctor thinks you might have an ectopic pregnancy he or she will ask you about your symptoms and about other things that might make ectopic pregnancy more likely, such as having had one before.

Your doctor will also examine you physically. But he or she might not be able to tell much from this. You will probably need to have two types of test:

• A pregnancy test, to tell whether you are pregnant. This could be a urine test or a blood test, or possibly both.

• An ultrasound scan. If you are pregnant this will detect whether the pregnancy is developing inside or outside the uterus.

While an ultrasound can show if your pregnancy is not developing in the uterus, it might not be able to show where exactly it is developing. Most ectopic pregnancies develop in the fallopian tube. But they can also develop in other places, including the ovary and the abdomen.

What will happen?

With treatment, an ectopic pregnancy can be safely ended. For more information on treatments for ectopic pregnancy, see our leaflet Ectopic pregnancy: what treatments work?

If you become pregnant again after having had an ectopic pregnancy you should see your doctor as soon as possible to check that the pregnancy is growing normally and in the right place.

Women who have had one ectopic pregnancy have an increased chance of having another. But most women are able to have a healthy pregnancy in the future.