To establish a successful pregnancy, an embryo needs to attach or ‘implant’ in the womb. In some cases of failed implantation, it is thought that the embryo doesn’t implant because the lining of the womb isn’t providing the right environment.
The endometrial scratching (ES) procedure is thought to trigger the body to repair the site of the scratch, releasing chemicals and hormones that make the womb lining more receptive to an implanting embryo. It is also suggested that the treatment could activate genes that make the womb lining more receptive to embryos.
Endometrial scratching before fertility treatment can help women who have had failed IVF treatments to improve their chances of implantation, so may be an option if you have been through miscarriages or if you have had unsuccessful treatments before.
Some studies have suggested that ES might be useful if you have had multiple failed fertility treatments in cycles where good quality embryos were transferred but the CARE team has not seen this benefit.
You can have endometrial scratching if you are having IVF with your own eggs - fresh or frozen, and with donor eggs.
Endometrial scratching is similar to a smear test, so while it can be a little uncomfortable there’s usually no need for pain relief or sedation.
We’ll very gently scratch the lining of your womb, also known as the endometrium. This causes a release of hormones in order to begin a repair process. Evidence suggests that this process makes the endometrium more receptive to embryos, which means it could improve your chances implantation and therefore of a successful treatment.
The optimum time for the procedure is in the cycle before your IVF treatment. The best time is often day 21 of your cycle, however if you have an irregular menstrual cycle the timing could be different. Your consultant will advise you of the optimal date.
Are there any risks?
There is a risk of infection with any transcervical procedure that may require treatment with antibiotics but this happens in fewer than 5% of cases The risk of perforation with any uterine instrument is ~1:500 so is uncommon.
There is a small risk that if you have an infection within your cervix before ‘scratching’, this may cause the infection to spread up into the uterus. Your clinic can treat this if necessary.
What are the side effects of endometrial scratching?
ES can cause period like pain or cramping and/or a small amount of spotting or bleeding after the procedure but the discomfort should be manageable with over the counter pain relief. Around 1 in every 200 women having this type of procedure may feel faint afterwards but this is usually brief and we will make sure you are feeling well before you leave the clinic.
What’s the evidence for endometrial scratching?
The independent regulator of fertility treatment, the Human Fertilisation and Embryology Authority (HFEA), has developed a ‘red-amber-green’ rating system and provides information on their website about treatments that are offered on top of your routine fertility treatment – known as treatment add-ons. They consider that the only way to be confident that a treatment is effective enough to be used routinely is to carry out a randomised controlled trial (RCT). In an RCT, patients are assigned randomly to two groups: a treatment group, given the new treatment and a control group, given a well-tried treatment or a placebo.
The HFEA has given ES an amber rating because the evidence for its effectiveness is based on a small number of moderate quality studies. The HFEA website notes that there are larger RCTs in progress but findings suggest that the benefits of ES may be less certain than initially thought.