We hope as many women as possible will participate in this study but not all pregnant women will be suitable. Please read the sections below to make sure that the study is right for you.

You may be able to participate if

You are pregnant, in your first trimester and between 18-40 yrs old

Please do not participate if any of the following apply to you:

You have diabetes

You have any mucopolysaccharide diseases

You are taking any systemic medications which are known to affect vision

Your pregnancy has been facilitated by IVF

You have a drug or alcohol addiction

You are a vulnerable adult (e.g., have safeguarding issues, mental health issues)

You have any eye diseases which are known to affect vision. This does not include short-sightedness, long-sightedness, and astigmatism and it is fine to participate in the research if you have these conditions and wear glasses or contact lenses.