Ectopic pregnancy

Health and Nutrition > Diseases > P Reviewed by Dr Philip Owen, consultant obstetrician and gynaecologist

What is an ectopic pregnancy?

An ectopic pregnancy occurs when the fertilised egg attaches itself outside the cavity of the uterus (womb).

The majority of ectopic pregnancies are found in the Fallopian tubes.

In rare cases, the egg attaches itself in one of the ovaries, the cervix (neck of the womb) or another organ within the pelvis. An ectopic pregnancy is not usually capable of surviving and in most instances an embryo is not developed. An ectopic pregnancy will spontaneously miscarry.

The majority of women diagnosed will have to be operated on or treated with medication.

What are the symptoms of an ectopic pregnancy?

The most common symptoms and findings of ectopic pregnancy are:

- an overdue period (suggesting pregnancy)
- bleeding from the vagina
- positive pregnancy test
- lower abdominal pain
- fainting.

At first an ectopic pregnancy develops like a normal pregnancy and the same symptoms such as nausea and tender breasts will be present. However, some women do not have these symptoms and do not suspect that they might be pregnant.

The vaginal bleeding can vary from being slight or brown vaginal discharge to being like a normal period.

If you are pregnant and have a long-lasting throbbing in one side of your lower abdomen or if you experience sudden pain you should contact your doctor. This is important because an ectopic pregnancy can be life-threatening if it ruptures and causes internal bleeding.

Why does an ectopic pregnancy occur?

In a normal pregnancy, the egg is fertilised by the man's sperm in the Fallopian tube and is then transported into the cavity of the womb where it attaches itself. This is called implantation. This transportation is made possible by the tiny cilia (finger-like projections) in the delicate inner lining of the Fallopian tubes that push the fertilised egg along.

Risk factors may be present that increase the likelihood of a woman experiencing an ectopic pregnancy. These are:

- previous surgery to the Fallopian tubes or previous inflammation of the Fallopian tubes (pelvic inflammatory disease). Because the lining of the Fallopian tubes is so delicate, inflammation or trauma can cause the cilia to beat in an abnormal fashion so that the fertilized egg implants in the wrong place.
- previous ectopic pregnancy. If you have previously had an ectopic pregnancy, the chances of another one in the same Fallopian tube and in the other tube are increased.
- becoming pregnant while using a contraceptive coil or the progestogen-only contraceptive pill (mini-Pill).
- becoming pregnant with in vitro fertilisation (test-tube methods). When using the test-tube method to overcome infertility one or more eggs are inserted into the woman's uterus.

Despite being placed within the womb, the fertilised egg may still attach itself to the wrong area outside the cavity of the uterus.

However, many women experiencing an ectopic pregnancy do not have any of these risk factors.

How is an ectopic pregnancy diagnosed?

. A urine test for pregnancy will nearly always be positive but it might be only weakly positive. In cases of doubt, a blood pregnancy test may be performed, which is always positive in ectopic pregnancy.

In the case of ectopic pregnancy, the uterus will often be smaller than expected for the number of weeks since the woman's last period and this can be checked by an internal pelvic examination. The doctor might feel a tender swelling corresponding to an ectopic pregnancy.

An ultrasound scan will help the doctor differentiate between a possible miscarriage, a continuing pregnancy inside the womb and an ectopic pregnancy.

Further investigation depends on the woman's symptoms, the scan findings and the level of pregnancy hormone (HCG) in the woman's blood. If there is uncertainty about the diagnosis then waiting 48 hours and measuring the level of HCG again is often appropriate.

How is an ectopic pregnancy treated?

If an ectopic pregnancy is strongly suspected then the gynaecologist will perform a laparoscopy to confirm the diagnosis.

Laparoscopy is performed through small incisions on the abdomen and the ectopic pregnancy can usually be removed in this manner.

The Fallopian tube in which the ectopic pregnancy occurred is often, but not always, removed at the same time. However, in some instances, open surgery becomes necessary in which the pregnancy is removed through a larger incision above the pubic hair line. This option is usually chosen if technical problems occur during the laparoscopy or if the internal bleeding in the abdominal cavity is difficult to control.

An alternative treatment to surgery is a medicine called methotrexate, which decreases the growth of cells in the ectopic pregnancy (unlicensed use). As a result the pregnancy shrinks and eventually disappears. The advantage of methotrexate is that it avoids the need for surgery but success rates with methotrexate tend to be slightly lower than with surgery. Occasionally, both surgery and methotrexate will be necessary.

What about future pregnancies?

The outlook for future pregnancies depends on several factors, especially whether the other Fallopian tube appeared normal or not.

As a general guide, after one ectopic pregnancy, 20 per cent of women will experience another ectopic pregnancy, 30 per cent will not become pregnant again and 50 per cent will have a successful pregnancy inside the womb.

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