The Early Pregnancy Observational Study (EPOS): following women throughout pregnancy to understand miscarriage

In order to understand miscarriage better, Tommy’s researchers have followed over 1,500 pregnant women throughout pregnancy. They have collected a huge amount of information from these women and are now using this to find ways of predicting the chances of miscarriage.
  • Authors list

    Professor Tom Bourne, Professor Phillip Bennett, Dr David MacIntyre, Dr Maya Al-Memar, Professor Christoph Lees, Dr Hanine Fourie and external collaborators

    Start date: 2016    
    End date: 2024

Why do we need this research?

Up to one in five women will experience a miscarriage in their lifetime and 1% of women will suffer three or more miscarriages. We still don’t know enough about miscarriage, which means that many women do not get an explanation as to why it happened to them or an indication of how likely it is to happen again in the future.

We need better tests to accurately predict the likelihood that a woman will have a miscarriage, whether they’ve had one in the past or not.

What’s happening in this project?

To understand miscarriage better and find ways to predict and prevent it, Tommy’s are supporting The Early Pregnancy Observational Study (EPOS). This study has followed more than 1,500 women from five weeks of pregnancy through to birth; 230 of these pregnancies sadly ended in miscarriage.

Our researchers have been looking at donated blood, urine and vaginal swabs from these women to look for bacteria or other substances that could help us understand why miscarriage happens. Samples were collected every two weeks during the first trimester of pregnancy, and then once during each of the second and third trimesters. The team also carried out an ultrasound scan of the baby and collected information about each woman’s clinical history and the outcome of their pregnancy. 

By working with so many women, our researchers have collected a huge amount of data that can be used to find out more about miscarriage. For example, our researchers have already found that women who miscarry during the first trimester are more likely to have lower amounts of a type of bacteria called Lactobacillus in the vagina. They have also found that a hormone called kisspeptin is present in lower levels in women who eventually miscarry. Our researchers have used these, and their other findings, to build models that can be used to predict how likely it is that a woman will have a miscarriage in the first trimester, and now want to find out whether the use of these models has a psychological impact on women.

Our researchers also want to use the EPOS study to continue exploring whether it is possible to identify if a miscarriage happened because of a genetic abnormality. They will do this by studying cell-free fetal DNA – DNA from the baby that is shed from the placenta into the mother’s blood – at the time of miscarriage. They also plan on performing a study to find out if treatment with a probiotic can help to prevent miscarriage in women who attend an early pregnancy unit. As an additional focus, the team are using data from EPOS to find out more about whether COVID-19 infection during pregnancy can lead to miscarriage or other complications later in pregnancy.

Finally, the team are now planning the EPOS-2 study, which will be used to validate the findings of the original EPOS project in an even larger group of women. The EPOS-2 study will focus on the earliest stages of pregnancy – before it is even possible to assess the viability of a pregnancy on an ultrasound scan and when interventions to prevent miscarriage are most likely to be effective.

What difference will this project make?

Our researchers believe that EPOS will help them to understand why miscarriage happens, and hope that their predictive model can be validated and eventually introduced into clinical practice. This could lead to problems being detected earlier, enabling healthcare providers to give the best possible care and allowing women and their families to prepare emotionally for the possibility of having a miscarriage.

Thanks for your interest in our research

Tommy's funds research across the UK investigating the reasons for miscarriage, stillbirth and premature birth. We can keep you updated on ways you can support our work. If you would like to join our fight against baby loss and premature birth, click here.