What is an ectopic pregnancy?
This is a pregnancy that implants outside the uterine cavity. The most common ectopic site is in the fallopian tube. It could, however, occur elsewhere such as in the cervix, ovary or pelvic cavity. Our discussion here will focus on the fallopian tube ectopic pregnancy, which accounts for well over 95 per cent of all ectopic pregnancies.
How common is ectopic pregnancy?
In the UK, one in every 300 pregnancies is ectopic. In the USA, the rate is higher, at one in 100. There is evidence that rates in most of the western world are going up.
What causes a pregnancy to implant outside the womb?
Causes are not always apparent but previous infection is an important predisposing factor.
Pelvic infection, especially if there is delay in treatment, causes tubal damage. The residual scarring inside the tube may impede transportation of the fertilized egg towards the womb. This may lead to ectopic implantation.. Chlamydia infection is particularly implicated, especially since it can be an entirely silent infection.
Other minor factors include surgery on the tubes (sterilization and reversal of sterilization) and some methods of assisted conception.
It is a widely held belief that intra-uterine contraceptive devices may increase the risk of ectopic pregnancy. Is this true?
This may sound like tortured logic but, in a word, no. The device (or "coil", as many people call it) will not increase the risk of ectopic pregnancy. However, the family planning practitioner advising a client has to ensure this is a suitable method for her.
The "coil" is certainly unsuitable for a woman with multiple potential or real partners. This is because she is at risk of pelvic infection, which puts her at risk of ectopic pregnancy. A "coil" protects against normal intra-uterine pregnancy, so the combined oral contraceptive pill will be a better option for her.
What about the "Mirena®," device?
This is a different matter. The Mirena device or "intra-uterine system", as its manufacturers prefer to call it, is a special type of device that contains a reservoir of a progestogen hormone. The hormone is released at a steady controlled rate in minute amounts to act on the wall of the uterus.
It is an extremely effective contraceptive, protecting against both intra-uterine and ectopic pregnancies. It has an added bonus in that it reduces the menstrual loss to very low levels within about three months of insertion, and its effectiveness may last up to five years.
What are the symptoms of an ectopic pregnancy and how can a woman suspect she might have it?
Symptoms vary quite widely. The most common symptom will be that of persistent and one-sided abdominal pain. The area will be tender to touch. This is usually - but by no means always - accompanied by vaginal spotting, light bleeding or simply a brownish discharge.
The symptoms typically start one or two weeks after missing a period. Sometimes the symptoms may start so early that the woman may be unaware she is pregnant. A woman with such symptoms should seek immediate medical help.
How is ectopic pregnancy diagnosed?
When a woman has these symptoms in early pregnancy, two essential tests (in addition to physical examination) will be done: a urine pregnancy test and an ultrasound scan.
Physical examination may reveal features that may strengthen the doctor's suspicion of an ectopic pregnancy but will not conclusively establish the diagnosis.
If the pregnancy test is positive, this is where an ultrasound scan comes in. If the scan shows the pregnancy in the uterus, then an ectopic pregnancy is virtually ruled out. If the uterus is empty, it strongly suggests an ectopic pregnancy. It is, however, not a foregone conclusion. The doctor has to look at the whole picture and decide whether or not the case he or she is dealing with is likely to be an ectopic pregnancy or not.