Implantation test for endometrial receptivity

Study to develop a new test for the lining of the womb in order to identify the cause of some repeated miscarriages.


The current investigations for recurrent miscarriage fail to identify the cause for more than half of the occurrences. This leads to frustration and increased anxiety for future pregnancies where no specific treatment may be offered to treat a particular cause of miscarriage.

It is well accepted that embryos are responsible for one third of implantation failures, while the lining of the womb accounts for the remaining two thirds. None of the existing tests for the quality of the lining of the womb is sufficiently accurate to predict the fate of a future pregnancy. This means we can’t really assess how prepared the lining of the womb is for nurturing and supporting the growth of pregnancy.

Identifying problems at the level of the lining of the womb is the first step towards treating them with an aim to reduce the risk of a future miscarriage.

Study design

The study was conducted across 5 hospitals in the UK (Birmingham, Newcastle, Chester, Manchester, Bristol and Essex). We identified a group of women who suffered unexplained repeated miscarriages without having any of the known risk factors for miscarriage (advanced age, high BMI, irregular periods etc). This made it more likely for the lining of the womb to be a potential cause for their miscarriages.

All the participants underwent a biopsy from the lining of the womb in a particular time of the menstrual cycle when the embryos are most likely to implant (what we call ‘implantation window’, somewhere in the second half of the menstrual cycle).

The biopsies were then processed and analysed in the lab to look at thousands of molecules that are specific to every woman.

We are currently comparing the molecules from women who suffered two or three miscarriages with the molecules from women who suffered a higher number of miscarriages in order to identify differences and potential clues of problems related to the lining of the womb.

What’s next?

We plan to follow up women who participated in this study and group them based on the outcome of their future pregnancy in either a healthy pregnancy that leads to a baby or a pregnancy with problems that leads to another miscarriage. Because we have already ruled out the known causes of miscarriage when we recruited the women for the study we believe that future miscarriages are likely to be caused by problems with the lining of the womb and we hope to identify these problems by comparing the molecules between the two groups.

Once we identify potential problems then we can develop treatments to address them and hopefully prevent future miscarriages caused by the lining of the womb.