Ectopic pregnancy occurs when an early pregnancy implants outside of the womb. It can implant in several places, such as on the ovary, higher in the abdomen, on the cervix or at the join between the tube and the womb (cornua), but the most common place is inside the fallopian tube. Pregnancy can even occur in both the womb and the tube at the same time (which is called a heterotopic pregnancy), but this is rare, affecting only about 1/10,000 pregnancies.

How common is it?
Ectopic pregnancy happens in about 0.25-1% of all pregnancies. It is, however, getting more common - probably related the increasing incidence of sexually transmitted infections, particularly chlamydia.

What causes the ectopic pregnancy?
Many factors are known to increase the chance of having an ectopic pregnancy. Anything that alters the way the fallopian tube works may affect future pregnancies. The 'tubes' aren't like a hollow pipe that just sits there with the egg rolling down through it. They have little hairs on the inside (cilia) which move with a wave-like motion to encourage the egg toward the womb. If the tube becomes blocked or the cilia damaged then an ectopic is more likely.

Often none of the risk factors below are present and there is no obvious reason - it was just bad luck.

• Advancing age
• Pelvic inflammatory disease - eg. previous chlamydia or gonorrhoea. Infection causes scar tissue adhesions in the tube and may damage the cilia. PID is one of the main causes of the increase seen in ectopic pregnancies in recent years. Risk of an ectopic increases about 7-fold after a woman suffers acute pelvic infection.
• Tubal surgery - women who have had operations on their tubes are more at risk of ectopic. This includes initial sterilisation, reversal of sterilisation or tubal surgery for a previous ectopic.
• Previous ectopic - about 10-20% of those attempting pregnancy after one ectopic will have another.
• DES exposure - this is a drug that was once used during pregnancy, until it was found that female babies of women who used it were at risk of developmental abnormalities of the genital system. Their tubes are more likely to be abnormal and predispose to ectopic pregnancy. This is a very rare problem and if you had it, you would most likely already know about it.
• Previous termination of pregnancy - the risk of ectopic increases among those who have had two or more terminations, particularly if there was infection afterwards.
• IVF (test-tube baby) and ovulation induction - both these techniques of assisted reproduction are associated with increased chances of ectopic pregnancy.

How would I know if I've got an ectopic?
Ectopics tend to present in one of three ways:

1. As an emergency. Suddenly, without warning a woman is very unwell, collapses and is taken to hospital. A positive pregnancy test is found and she is transferred to theatre right away and a ruptured ectopic is found with bleeding into the abdomen.
2. The second group includes women who are known to be at risk of an ectopic pregnancy, for example she may have had an ectopic previously, may have undergone tubal surgery or assisted conception (such as IVF). Early detection of ectopics are high in this group of women as we routinely check that the pregnancy is where it should be fairly early on. Less than 20% of ectopics present this way.
3. Finally, the most common presentation is with a missed period, positive pregnancy test, some pelvic pain (usually to one side), and some irregular vaginal bleeding. Some women report fainting or shoulder-tip pain.

What tests are used to diagnose ectopics?
Obviously first of all a pregnancy test. If a sensitive urinary test is negative then ectopic pregnancy is very unlikely. This may be backed up with a blood sample being taken.

Ultrasound scan can reliably demonstrate a pregnancy in the womb from about four and a half to five weeks of pregnancy. At this early stage the scan will need to be done using transvaginal sonography (TVS). Once the pregnancy is seen in the uterus, an ectopic is once again virtually excluded (except in the case of the extremely rare heterotopic pregnancy). Sometimes a scan may show an ectopic pregnancy clearly in the tube next to the womb, but this is less common.

Unfortunately, there is about an 11-14 day window when a pregnancy test may be positive, but it is too early for ultrasound scan to confirm exactly where it is. In this case, it is important to watch for change in clinical signs, such as worsening pain, more tenderness on examination, fall in blood pressure, etc. This may mean staying in hospital until it is sorted. We can also check the exact level of the pregnancy hormone (hCG). In a normal pregnancy this should go up by at least 60% every 48 hours; in an ectopic it may climb at a lower rate or plateau. The clinical signs and blood tests guide who should undergo laparoscopy.

Laparoscopy means having a general anaesthetic. A telescope is placed into the abdomen and the tubes visualised. This is the 'gold standard' for diagnosing ectopics, but it isn't done for everyone because of the need for an anaesthetic, and the modest risks of the procedure.

What are the treatments?
Once an ectopic is diagnosed, there are several different treatments. It is not possible to take the pregnancy from the tube and put it into the womb. The options are as follows:

• Expectant management - some ectopics will not progress to tubal rupture, but will spontaneously resolve and be slowly absorbed. This may be appropriate if the level of hCG is falling and a woman is clinically well.
• Medical treatment - with a drug called methotrexate, which is given by injection. This makes the ectopic pregnancy shrink away by stopping the cells dividing. Only a few ectopics can be treated this way, which is the least invasive. Certain criteria must be fulfilled, such as small diameter of the ectopic on scan and low level of hCG. Close follow-up with further scans and blood tests is also necessary.
• Laparoscopic surgery - via 'keyhole' surgery, it may be possible to either open the tube and remove the pregnancy (salpingotomy), or remove the tube altogether (salpingectomy). The decision on which of these options is taken is very specific to each patient. Follow-up with blood tests for hCG will more than likely be needed as persistent ectopic tissue can occur in 5-10% if the tube is not removed.
• Open surgery (laparotomy) - this involves a 5cm incision at the top of the pubic hairline. The affected tube is brought out and either salpingotomy or salpingectomy performed.

What about further pregnancies?
Of course in the future you may wish to try again for a pregnancy. As I mentioned above, after having an ectopic pregnancy, the chance of it happening again is higher (though it is usually still more likely that the next pregnancy will be in the right place).

All the above treatments have been evaluated in clinical studies to see what the future pregnancy rate is like. It is very difficult to compare these exactly as every case is different, not all women try for a further pregnancy again and surgeons use different techniques. What does come out of this research is that methotrexate, open surgery and laparoscopic surgery all have pretty similar rates of normal pregnancy next time.

The risk of another ectopic depends on several factors, in particular the type of surgery that has taken place, whether or not there is any damage to the other tube and whether there were any difficulties falling pregnant the first time around.

Studies that compare removing the tube (salpingectomy) with opening it at the time of surgery and removing the pregnancy (salpingotomy) have found that when the other factors above have been controlled for, the risk of repeat ectopic is about 9% if the tube is removed and 12% if the tube is left behind. There is no difference in outcome whether the operation was an open one or key-hole surgery was used (laparoscopy), but recovery is certainly quicker with the key-hole option.

So why leave the tube at all if it leads to more ectopics? The first reason is that if another ectopic were to occur and the salpingectomy had to be performed this time around, the only option for pregnancy in the future would be test-tube pregnancy (IVF). The other reason is that although the ectopic risk is slightly higher, the normal pregnancy rate may be improved if the tube is conserved. In women who have had no difficulty getting pregnant, the normal pregnancy rate is 70-85% whether salpingectomy or salpingotomy was performed. For women who had difficulty conceiving the first time around, the subsequent normal pregnancy rate is around 10% if the tube was removed and 25% if it is conserved.

Note that these figures are from studies and are averages; your surgeon should be able to give you a much better idea of the risk specific to you. A young woman who has otherwise a completely normal pelvis with a healthy second tube will have much lower chance of another ectopic than one who has severe pelvic scar tissue (adhesions) and a damaged other tube.

It is easy for people to forget during all of the investigations and surgery that you have lost, what is for most, a much wanted pregnancy. Reaction to a pregnancy loss is very variable and in addition to the grief you may feel, your body will be undergoing some profound hormonal adjustments, which may make you feel very emotionally volatile. Don't be surprised if you find yourself in tears for no apparent reason. It may take some time for you to get on your feet again, that is certainly normal.

View here a video of surgical treatment of an ectopic pregnancy.

Additional information:
Miscarriage Support - Ectopic pregnancy
Ectopic pregnancy at NeLH Women's Health - an NHS site providing best practice guidance for UK health professionals.

Danny Tucker
Obstetrician and Gynaecologist