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The purpose of the CLARITY study is to help understand more about the heart and blood vessel changes that occur in young adults born to pregnancies complicated by high blood pressure (hypertension).

Study Background

Children born to hypertensive disorders of pregnancy are, like their mothers, also more likely to develop hypertension in later life as well as being at risk for major events such as stroke. We, and others, have shown they display specific patterns of altered cardiac, cerebral and vascular development similar to those observed in the mothers, in childhood, adolescence, and young adulthood. They are independent of other factors related to the pregnancy of their mother such as degree of prematurity or growth restriction and such findings raise the possibility that unique patterns of hypertensive disease progression may be identifiable across generations of families affected by hypertensive pregnancy.

Our primary aim is to understand hypertensive disease progression over the life course of people born to a hypertensive pregnancy. We will use this information to address our secondary aim, which is to develop clinical approaches to prevent early onset cardiac, cerebral and vascular disease in these individuals.

Study Objectives

We know that children born to pregnancies complicated by high blood pressure tend to have higher blood pressure and are more likely to have similar problems during their own pregnancies. This project will help us understand more about how changes in the blood vessels, heart and brain develop, using methods including ultrasound imaging and magnetic resonance imaging of the heart. The data will be used to better understand the relevance of any alterations in the heart of young adults, particularly in those born to pregnancies complicated by high blood pressure. We hope this study can eventually lead the development of new ways to prevent early onset of heart and blood vessel disease.

Study Recruitment

We are undertaking a follow-up of 200 young adults from the Avon Longitudinal Study of Parents and Children (ALSPAC) study, a longitudinal birth cohort study based at the University of Bristol. Of the 200 young adults followed up from the ALSPAC study, 100 will have been born to a hypertensive pregnancy and 100 following an uncomplicated pregnancy. At time of follow-up, they will be 30 to 40 years of age.

 Study Visits

There is one study visit as part of the CLARITY Study which will last up to 4 hours. This visit will take place at the John Radcliffe Hospital in Oxford. The visit will include an MRI scan and echocardiography (ultrasound) to take pictures of the heart, lung function assessment (spirometry), exercise testing, recordings of blood pressure, as well as retinal and ear microvascular imaging (collecting images of the small blood vessels in the back of the eye and the ear), and blood sampling. During this visit, we will also collect demographic and anthropometric data, and you will be asked to complete a questionnaire. The study visit will finish with you being provided with a wrist worn activity tracker to wear for 7 days.

Research Funding

The study is supported with funding from the Medical Research Council.

Study Approvals

The study has been approved by the Wales Research Ethics Committee 6 Research Ethics Committee (Reference 22/WA/0227).

Stylized heart illustration with 'CLARITY' wording underneath