Endometrial biopsy (or “endometrial scratch”) is a technique that is increasingly being used as part of IVF treatment. It’s a relatively simple thing to do – it involves passing a catheter through the neck of the womb (the cervix) into the uterine cavity and taking a small sample of the inner uterine lining (called endometrium), and sending it for analysis. A bit like a Pap smear, but “higher up”. It’s a bit unpleasant but only takes a minute – I do most of them in my office without needing day surgery or any anesthetic agents.
Now here’s the interesting bit. This technique was developed because doctors have been trying to find out who might have a problem with their uterine lining that is stopping embryos from implanting at IVF. But it turns out that very often, we don’t find anything wrong – but the doing of the test itself can help embryos to implant.
Why is this so? Well, we aren’t really sure – but the small damage that is done to the endometrium might somehow activate it to be more receptive. There are certainly someongoing studies around the world suggesting higher pregnancy rates if the biopsy is done late in the cycle before the IVF cycle, or perhaps in the first few days of the IVF cycle itself. There seems to be value whether the planned embryo transfer is of a fresh or frozen embryo.
Like all new developments, we are still not sure who really benefits and I’m not sure that every patient should rush to have a biopsy in association with each embryo transfer. Repeated sampling might put the patient at risk. But if a patient has what appears to be healthy looking embryos that don’t quickly take, then it’s a reasonable technique to consider.
My only real problem with the test is wondering why someone decided to call it “endometrial scratch” – I think it came out of Britain where tabloid newspapers love simplified terms – a bit like “three parent IVF” – but it seems we are now stuck with the phrase.