Endometrial scratching is rated amber because there is conflicting evidence from randomised controlled trials (RCTs) to show that it is effective at improving the chances of having a baby for most fertility patients.
What does this traffic light rating mean?
Our traffic-light rated list of add-ons consists of three colours that indicate whether the evidence, in the form of high-quality RCTs, shows that a treatment add-on is effective at improving the chances of having a baby for most fertility patients.
We give an amber symbol for an add-on where there is conflicting evidence from RCTs to show that an add-on is effective at improving the chances of having a baby for most fertility patients. This means that the evidence is not conclusive and further research is required, and the add-on should not be recommended for routine use.
Our traffic light ratings only indicate the effectiveness of a treatment add-on, at improving your chances of having a baby. Specific safety concerns about a treatment add-on are included under the dedicated section ‘Is this treatment add-on safe?’.
What is endometrial scratching?
In order to have a successful pregnancy, an embryo needs to ‘implant’ in the womb; if it doesn’t, the patient will need to start their cycle again.
Most embryos don’t implant because they’ve been unable to develop fully to the implantation stage or because of a developmental mismatch between the stage of the embryo and the lining of the womb.
However, in a small number of cases an embryo won’t implant because the lining of the womb isn’t providing them with the right environment.
Endometrial scratching, also known as endometrial injury, is carried out before IVF. During the procedure the lining of the womb (the endometrium) is ‘scratched’ using a small sterile plastic tube.
The theory is that this procedure triggers the body to repair the site of the scratch, releasing chemicals and hormones that make the womb lining more receptive to an embryo implanting. Some also suggest the treatment may activate genes that make the womb lining more receptive to an embryo implanting.
What’s the evidence for endometrial scratching?
Earlier studies were of poor quality and showed conflicting results. The current evidence base includes some quality studies and has shown that there could be a 0 - 5% improvement in live birth rate. However, due to conflicting results from other recent studies further evidence is needed before the benefits of endometrial scratching can be confirmed.
At the October 2021 Scientific and Clinical Advances Advisory Committee (SCAAC) meeting the Committee evaluated the evidence base for endometrial scratch. Minutes of this discussion and the evidence used to inform this discussion are available on the SCAAC webpage.
Is this treatment add-on safe?
Although this is an intrusive procedure, with some patients experiencing pain and blood loss, it is not common for patients to have an infection after the scratch. There is a small risk that if you have an infection within your cervix before ‘scratching’, this may cause the infection to spread into the uterus. Your clinic can treat this if necessary. Endometrial scratching does not carry any additional known risks for the child born as a result of fertility treatment.
If you have any questions about the safety and risks, your clinic will be able to discuss whether a treatment add-on would be safe for you to use considering your specific medical history and circumstances.
What are treatment add-ons?
- optional additional treatments, also referred to as ‘supplementary’, ‘adjuvants’ or ‘embryology treatments’.
- often claim to be effective at improving the chances of having a baby (live birth rate) but the evidence to support this for most fertility patients is usually missing or not very reliable.
- likely to involve an additional cost on top of the cost of a routine cycle of proven fertility treatment. Some treatment add-ons can cost hundreds or thousands of pounds each.
It is important to keep in mind that for most patients, having a routine cycle of proven fertility treatment is effective without using any treatment add-ons. If you are paying directly for your own treatment, you may want to think about whether it might be more effective and/or affordable to pay for multiple routine proven treatment cycles, rather than spending large sums of money on a single treatment cycle with treatment add-ons that haven’t been proven to be effective at increasing the likelihood of you having a baby.
We aim to publish clear and reliable information about some of the treatment add-ons that don’t have enough evidence, from high-quality randomised control trials (RCTs), to show that they are effective at improving your chances of having a baby.
To make it easier to understand the scientific evidence for each treatment add-on we have developed our traffic-light rated list of add-ons.
Review date: 4 January 2024