Does Chlamydia cause ectopic pregnancies?

Dear Professor Winston,

I have for a very long time wondered whether Chlamydia caused ectopic pregnancies. I was diagnosed with this disease back in 2007 and was treated with antibiotics which cleared it. I must have had it for 9 months and experienced no symptoms, but since went on to have three ectopic pregnancies which caused me enormous suffering – two in my left tube and one in my right.  I had a HSG in September 2013 which showed my womb to be fine but my left tube completely blocked which is where I had my first ectopic that was treated with Salpingostomy (my second in my left tube resolved itself naturally), and my right tube was clear, however after the procedure, in March 2014 I went on to have my third ectopic in my right tube, even though it was clear at HSG.  I have since managed to have a child via IVF, which bypassed by tubes, but still would love to have a another child without going through IVF. I have read that recent research suggests that Chlamydia may in fact not damage the tubes, as previously thought. I would love to know your thoughts on this.

Thank you.


Dear I.,

It is our research, with my colleague Gloria Vasquez, which showed that ectopic pregnancy follows inflammatory damage of the lining of the Fallopian tubes after an infection.  It is usually the hair-like cilia which move an egg along towards the uterus that get wrecked.

It is unclear whether Chlamydia causes this damage, though most people assert that it is an important cause.  I am very unconvinced as in various experiments, we did not find this kind of damage after different Chlamydia infections had been induced in different models.  And it is certainly true that most Chlamydial infections are probably very much less important and in any case don’t cause symptoms,  But it could be likely, of course, that you had another infection, not from Chlamydia, but from a bowel bacterium for example.  This is extremely common in my experience and may well not be related to sexual activity.

Ectopic pregnancy also occurs in people with certain abnormalities in the womb or the tubes, usually as a result of a congenital problem and can also occur after infections like appendicitis, or following surgical operations in the lower abdomen.

If you’ve had three ectopics you are fairly unlikely to get pregnant again spontaneously, but if you do you are more likely to have another ectopic even if most of the tube has been removed.  Ectopic pregnancy can also occur after IVF treatment as the embryo may leave the uterus briefly and lodge in the stump of one or other tube.

Yours sincerely

Robert Winston