18-20 Weeks

Your 20-week ultrasound scan checks your baby’s development and growth. This will be the last of your routine scans unless you experience any complications. The conditions this scan will be looking for as well as to check general development are:

Neural Tube Defect Spina Bifida

A condition that happens early in pregnancy but is not detected until around 20 weeks, where the spine does not develop properly causing a range of disabilities. Extra Folic acid during early pregnancy could reduce the risk.

Low-lying placenta

If the placenta is low or covering the cervix, you will be monitored as this can cause excessive bleeding during labour.


Pre-eclampsia is a serious but quite common pregnancy complication. A blood test is in development that can detect two substances in your blood that are released by the placenta, which it is believed could indicate pre-eclampsia and could be carried out at 12 weeks. The current test for pre-eclampsia is only effective after 20 weeks and is detected by checking for protein in urine (you will be asked to give a urine sample at every appointment). High blood pressure could also be a sign.