How the Miscarriage Support Tool works

The Tommy’s Miscarriage Support Tool is for women and birthing people who have had 1 or more miscarriages. It gives you personalised support and information if you are considering pregnancy after miscarriage. Based on information you put in, it can also tell you what the chance is of your next pregnancy being successful.

Watch a film of Professor Siobhan Quenby talking about the research behind the tool

The Miscarriage Support Tool can tell you what the chance is of your next pregnancy being successful (this means going at least to full term, which is 37 weeks).

The tool also gives you personalised support and information based on your results. 

It has been designed to give everyone access to information that is currently only available to women and birthing people who go through the clinics that are part of the Tommy’s National Centre for Miscarriage Research. 

The tool uses an algorithm based on a specific piece of research. The variables that have been found, as part of this research, to make a difference to pregnancy outcomes are: 

  • Age 
  • BMI (weight) 
  • PCOS (Polycystic Ovarian Syndrome) 
  • Number of previous miscarriages 
  • Number of previous live births 

Is this the complete list of things that can make a difference to your risk of miscarriage? 

No. The risk level that the tool gives you is the closest we can get based on the information you are giving us about the factors we have listed above.  

There are other factors, such as ethnicity and smoking, that are linked to miscarriage too, but we do not have enough data yet on these to include them (we hope to include them once we have enough data).  

If you are of Black or Black Mixed Heritage you can find more about the extra risks here.  

If you are a smoker, your chance of a successful pregnancy will be less than that shown on your tool result. Please find more information and support here about smoking before pregnancy and during pregnancy.

If you have had a late miscarriage you may also have several other risk factors depending on whether the cause of your late miscarriage was known or not. These include waters breaking early, infection or a weak cervix. These factors are not included in your calculation.

If you have an underactive or overactive thyroid, this is a known issue that is linked to miscarriage but is not included in your calculation. You can read more about the thyroid and miscarriage here.

Endometriosis is not included in your calculation. Our research doesn’t show a clear link between endometriosis and miscarriage. We’ve funded a number of studies in this area through our centre and none have given us clear, robust evidence. This is why we haven’t included this in the tool calculation. 

You can read more about the research about endometriosis and miscarriage here.

Does it include IVF or other types of fertility treatment?

The research the tool is based on did include people who became pregnant through fertility treatment and this was not shown to make a difference to the results. However, if you used donor eggs to become pregnant, then it is unlikely to be accurate for you as the result depends on the combination of factors, some of which you may not know.

What does my result mean? 

In the tool we give your result as a percentage chance.

It does not mean that you will definitely have (or not have) a successful pregnancy. 

If you got, for example, a 60% chance of a successful pregnancy it means that if you had a room of 10 women with the same answers (that you gave to the questions on Age, BMI, PCOS, Previous miscarriage and Previous live births) 6 of these would have a successful next pregnancy. 

How does it work? 

By entering your personal and medical information, as well as your pregnancy history, the calculator uses an algorithm to calculate your chance of a successful pregnancy.  

The algorithm has been developed by the University of Warwick and is based on data collected from the Tommy’s NET, a database created by Tommy’s National Centre for Miscarriage Research

Tommy’s NET collects and holds pregnancy information from participants who have taken part in our miscarriage research. So far, the team have collected data from over 1,800 women.  

Using the information, our teams have been able to discover what combination of medical history is common in those who have had miscarriages and what can affect the chance of a further miscarriage. 

This information is then used to create an algorithm (a process used by a computer that is used to solve a problem) to calculate the probability of a successful pregnancy. Once the algorithm was created, we tested whether it could compute accurate outcomes in a real-world setting. And it was found to work successfully. 

How reliable is the algorithm? 

Since its creation, the model has been scientifically validated (checked) at 4 other recurrent miscarriage clinics in the UK. This means the calculations have been tested, to the highest level, with other data collections, and performed successfully. An early 2022 an assessment of the quality of the data collected by Tommy’s NET found significant relationships between medical history and pregnancy outcomes, showing that it is possible to use this data as a model of prediction. 

What support does the tool give? 

The tool will be gathering a lot of information about you as you work towards getting a result. We can use this information to automatically personalise the advice we give you. That means we can narrow down the advice to your own circumstance, saving you time and making it easier for you to find out what you need to know. 

You are gathering data beyond what is needed for your algorithm. What future research will you be using it for? 

The extra questions that we ask in the tool, that are not used in the user’s calculation, will be shared anonymously with our research teams so that we can improve the scope of the algorithm, taking other medical history and pregnancy outcomes into account. Everything that we do is aimed at helping make pregnancy safer. 

How can I be sure my data will be safe?

We take your data safety and privacy very seriously here at Tommy's. Your personal data will never be shared with any third party to use for their own purposes. The data you give in the tool is used only as follows: 

  • Anonymous data is shared with our research teams so they can learn more about the risk factors for miscarriage. 'Anonymous' means that no personal data is shared.
  • If you say 'Yes' to finding out more information about what we do at Tommy's, for example our Miscarriage Matters campaign, we will email you with news about research, campaign and fundraising projects. You can unsubscribe from these at any time.
  • If you sign up to receive personalised support emails, you will get around 5 emails that offer you extra support as you consider a pregnancy after miscarriage. Once these have been sent, you will not get any more emails unless you have also said 'Yes' to get more general emails from Tommy's, as described above. You can also unsubscribe from these at any time.

Read more about our Privacy policy here.

How can I find my results again?

To get your results again:

  1. Go to
  2. Click on 'See Results'.
  3. Enter the email you gave when you went through the tool.
  4. A code will be sent to your email. Check junk/spam if you can't find it. 
  5. Return to the same page and enter the code. Your results should appear.

Miscarriage Matters campaign 

This project is a follow-on from the recent Miscarriage Matters campaign, which recommends specific, and personalised, care pathways for women who have an increased chance of having a miscarriage. 

Looking to the future 

As the data held within the Miscarriage Support Tool, and collected by Tommy’s NET, increases, this will allow us to increase the accuracy of our research. We hope that by creating the Miscarriage Support Tool we can provide women and birthing people with the most up to date advice and support that is easily accessible to everyone, anywhere. We want everyone to have the information they need to improve their chances of a successful pregnancy.

Tell us what you think

This is a new tool (launched in Nov 2022), we want to continue to improve it as we get feedback from people who use it. Please let us know what you think of it, whether you found it helpful and how we can improve it.

Quenby S, Gallos ID, Dhillon-Smith RK, Podesek M, Stephenson MD, Fisher J, Brosens JJ, Brewin J, Ramhorst R, Lucas ES, McCoy RC, Anderson R, Daher S, Regan L, Al-Memar M, Bourne T, MacIntyre DA, Rai R, Christiansen OB, Sugiura-Ogasawara M, Odendaal J, Devall AJ, Bennett PR, Petrou S, Coomarasamy A. Miscarriage matters: the epidemiological, physical, psychological, and economic costs of early pregnancy loss. Lancet. 2021 May 1;397(10285):1658-1667. doi: 10.1016/S0140-6736(21)00682-6. Epub 2021 Apr 27. PMID: 33915094. 

Khan O, Gour S, Lim Choi Keung SN, Morris N, Shields R, Quenby S, Dimakou DB, Pickering O, Tamblyn J, Devall A, Coomarasamy A, Thornton DK, Perry A, Arvanitis TN. Electronic Patient Reported Outcomes for Miscarriage Research in Tommy's Net. Stud Health Technol Inform. 2022 Jun 29;295:458-461. doi: 10.3233/SHTI220764. PMID: 35773910.  

Shields R, Khan O, Lim Choi Keung S, Hawkes AJ, Barry A, Devall AJ, Quinn SD, Keay SD, Arvanitis TN, Bick D, Quenby S. Quantitative assessment of pregnancy outcome following recurrent miscarriage clinic care: a prospective cohort study. BMJ Open. 2022 Feb 2;12(2):e052661. doi: 10.1136/bmjopen-2021-052661. PMID: 35110317; PMCID: PMC8811565.