An ectopic pregnancy occurs when a fertilized egg implants outside of the uterus. The incidence of ectopic pregnancy varies enormously between countries, for example, 1.24 per cent of pregnancies are ectopic in the United Kingdom compared with 4 per cent in Ghana. The method of conception also has an effect, for example, after in vitro fertilization (IVF), the incidence is as high as 4-11 per cent.
The most common site for an ectopic pregnancy is the Fallopian tube. More rarely, an ectopic pregnancy occurs in the ovary or positive in ectopic pregnancy? abdominal cavity.
Risk factors for an ectopic pregnancy include:
- A previous ectopic pregnancy
- A history of pelvic inflammatory disease (for example, chlamydia infection)
- Previous tubal surgery (for example, reversal of a sterilization procedure)
- Conception while on the mini-pill or with a coil in place
- Fertility treatment (for example, ovulation induction or in vitro fertilization).
Most women with an ectopic pregnancy complain of a missed or abnormal last period, vaginal bleeding or abdominal pain. However, not all women have these classic symptoms. Therefore an ectopic pregnancy should be suspected in any woman of reproductive age who has abdominal pain.
Ectopic pregnancy can be life-threatening. The main danger occurs when the pregnancy occurs in the Fallopian tube and causes a rupture in the Fallopian tube, in which case major internal bleeding can occur, resulting in shock and collapse.
Early diagnosis is vital whenever an ectopic pregnancy is suspected, for example, when the uterus is found to be empty or, in some cases, when a mass is seen next to the uterus.
Investigations such as an ultrasound scan - which is often performed transvaginal!/ - and blood tests are useful in diagnosis. A laparoscopy will enable the obstetrician to inspect the Fallopian tubes and pelvis and will confirm the diagnosis.
The treatment of an ectopic pregnancy is aimed mainly at preventing major haemorrhage and most commonly involves an operation on the affected Fallopian tube. It may be necessary to remove the tube, or the ectopic pregnancy itself can be removed while preserving the tube. Nowadays, this can often be done by using keyhole surgery, but it may be necessary to make an incision (usually just below the bikini line) in the abdomen, particularly if the ectopic pregnancy has ruptured the Fallopian tube. If the tube ruptures, a blood transfusion may be necessary.
In some cases, it may be possible to treat a small ectopic pregnancy with powerful drugs designed to stop it growing, thereby avoiding the risk of it rupturing or the need for surgery.
The conditions that originally gave rise to the ectopic pregnancy, and its treatment, may affect subseguent fertility. Only about one third of women trying to become pregnant after an ectopic pregnancy will be successful. A significant number (15-20 per cent) will have another ectopic pregnancy.
In subsequent pregnancies women who have had a previous ectopic pregnancy will usually be advised to have an early ultrasound can at about 7 weeks gestation to determine whether the pregnancy within the uterus or not.