Tanya Horne, an obstetric sonographer, explains what is involved in routine scans that are undertaken at 12 and 20 weeks.

These are screening tests that enable medical professionals to check the baby's health and rate of growth. These procedures are non-invasive and usually last about 25 minutes. 

It is not unusual for women to have scans at other points during their pregnancy, for example, if they have a low lying placenta.

During the 12-week scan the sonographer carries out a series of checks, such as examining the baby's heartbeat and limbs, as well as the amniotic fluid.  The baby will also be measured, which gives an accurate expected date of delivery.

During the 20-week scan the sonographer looks at the baby in more detail, checking the brain, spine and major organs. 

Tanya was working at Warwick Hospital maternity unit in 2011.

Due for review August 2013.