Ectopic pregnancy – top 10 risk factors
An ectopic pregnancy means your pregnancy has started in the wrong place. An embryo should develop inside your womb. But an ectopic pregnancy happens outside it. Almost all ectopic pregnancies occur in one of the fallopian tubes. Much more rarely, in the abdomen, ovary or cervix.
It’s a big problem. A pregnancy outside the uterus can’t survive. What’s more, it can be life-threatening for you if it’s not quickly treated. 1 in 100 pregnancies are ectopic. That’s actually quite a lot. 30 per cent happen for no good reason. For the remaining 70 per cent, here are the top 10 risk factors.
1. Previous surgery.
If you’ve had past surgery on your fallopian tubes, this can increase your ectopic risk. So can other forms of abdominal surgery, such as a Caesarean section, sterilisation reversal or having your appendix out.
2. Structural problems.
Having structural issues with your fallopian tubes (e.g. an unusually shaped tube) can cause difficulties. If your tubes are damaged, they can become scarred, inflamed or narrower – all of which make it harder for a fertilised egg to travel to your womb. That increases the risk of the egg implanting where it shouldn’t.
Smoking ups your risk of an ectopic pregnancy too. Research reveals that smoking increases levels of a protein called PROKR1 in the fallopian tubes, making them function less well. This increases the chance of the egg sticking to the inside of a tube. It’s a major reason to avoid smoking before and during pregnancy.
4. Previous ectopic.
If you’ve had an ectopic pregnancy before, it puts you at risk of another. That doesn’t mean you’ll definitely have one. But your risk is higher than for the average pregnancy.
5. Your age.
Being older – some studies say over 35, others say over 40 – seems to increase the risk of an ectopic pregnancy. Since more women are having children later in life, it’s another risk factor to take into account.
6. Pelvic inflammatory disease (PID).
Pelvic inflammatory disease (PID) is often caused by sexually transmitted infections like chlamydia or gonorrhoea. The bad news? It can affect the fallopian tubes. If you have PID – and sometimes you don’t know until you start trying for a baby – it can increase the risk of an ectopic pregnancy. PID makes the tiny hairs on the lining of your tubes less able to transport the egg to your uterus for implantation. PID can also cause scarring of your tubes – this is bad for egg transportation too.
Endometriosis causes the endometrial tissue and cells of the womb to grow in other areas of the pelvis. This renegade tissue has a monthly bleed too, which results in scarring and adhesions. The fallopian tubes are commonly affected by endometriosis. Scarring can cause them to become damaged, twisted or stuck to other organs. All this make it harder for a fertilised egg to pass through. Cue: a possible ectopic.
8. IUD and the mini pill.
Two forms of contraceptive are linked to higher ectopic risks: the IUD (or coil) and the progesterone-only birth-control pill. The latter is sometimes called the mini pill. But bear in mind that the chances of getting pregnant while using an IUD are low anyway.
9. Tied tubes.
This risk factor is perhaps not so surprising. If you’ve previously had your tubes tied (a procedure called tubal ligation) it can raise the likelihood of an ectopic pregnancy. Tubal reversal surgery is available: over half of women who have one can get pregnant. But all that surgery is tough on your tubes. Ectopics love battered tubes.
10. Fertility treatments and drugs.
IVF treatment is often used to help overcome tubal problems – after all, it bypasses the fallopian tubes. It also slightly increases the risk of an ectopic pregnancy. This is ironic. The theory is that if the embryo is placed too high in the womb (i.e. away from the MIP point) there’s a greater chance it can drift off course. That’s why you should always insist on the most senior doctor to do your embryo transfer.
Taking fertility medication to stimulate ovulation can also increase the risk. Research into fertility drugs and ectopics is still ongoing. Newly released research suggests the ectopic risk could be different for fresh and frozen cycles. More studies are needed.
In summary, despite these top 10 risk factors, it’s important to keep in mind that they’re just that: potential risks. They certainly don’t mean you’ll have an ectopic pregnancy – just that your chance could be slightly higher than the general population. So be mindful of the risks, but don’t panic.