I-test and I-test M

Investigating blood vessel changes to help predict pregnancy complications.

In the I-Test and I-Test M studies, we are looking for new ways to monitor health in pregnancy.

I-test aims to monitor changes in the blood vessels at the back of the mother/birthing person's eye, to see if this might be a new way of identifying those at risk of pregnancy complications. 

In I-Test M, we want to understand more about how changes in the blood vessels in the back of the eye are connected to changes in blood vessels in the rest of the body. This will help us to understand why some individuals develop pregnancy problems such as pre-eclampsia (dangerously high blood pressure in pregnancy) and fetal growth restriction (where babies do not grow at a healthy rate inside the womb).

We also hope to explore whether continuous monitoring with wearable or remote devices can pick up early signs of pregnancy complications.

These studies are recruiting participants in the first half of pregnancy, at 12 or 20 weeks of pregnancy (+/- 3 weeks). We are asking people with healthy pregnancies, as well as those who have developed pregnancy complications, to take part.

If you are more than 23 weeks pregnant, you may still be able to take part in the study by attending study visits in the later stages of pregnancy. Our study team will be able to advise you, so please contact us.


You will be invited to up to three study visits during your pregnancy, and one visit after your baby is born. These will be at the Royal Infirmary of Edinburgh.

During study visits we will conduct a range of non-invasive tests which give information about your heart and blood vessels. These involve sticking small sticky patches (electrodes) onto your skin and placing a small sensor or ultrasound probe over different points on your body, including over your womb to measure the amount of blood flowing towards your placenta and baby. The measurements are quick to perform, safe in pregnancy, and should not cause any discomfort. You will be shown the ultrasound pictures of your baby on a screen whilst we are taking the measurements.

We will take photographs of the back of both your eyes using a specialised camera (similar to a test you might have at a visit to the optician). We will also ask if we can collect urine samples and take (up to two) extra blood tests. This is to look for other markers which might predict pregnancy complications.

In addition, we will ask you if you would be happy to use a wearable device and/or a bed monitor (a small sensor that sits underneath your mattress) to collect data about your heart and blood vessels between study visits. This is optional – you can choose whether or not to collect this extra data.

Each visit will take between 1-2 hours, and you will be reimbursed for your time with a £50 voucher at the end of the study.


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