During your pregnancy, you'll be offered a range of tests, including blood tests and ultrasound baby scans.
They are designed to help make your pregnancy safer, check and assess the development and wellbeing of you and your baby, and screen for particular conditions.
You don't have to have any of the tests, but you need to understand the purpose of them so you can decide whether to have them or not.
Discuss this with your maternity team.
Public Health England have published a short animation explaining antenatal and new-born screening. You can see it here.