This scan is usually performed at 19 -20 weeks. A “head to toe” scan of the baby is done, and all major structures are assessed. At this stage, the sex of the fetus can usually be determined if requested. You will not be told the gender if you advise your sonographer that you wish to avoid knowing. 3D and 4D scans of the fetus will also be performed.
The distance of the lower edge of the placenta to the cervix will also be determined at this stage. If the placenta is low you will need a follow-up examination in the last 3 months of the pregnancy.
We will also measure your cervix (sometimes via an internal scan) as a shortened cervix has been linked to pre-term labour.
Note: mid-trimester ultrasound is not a recognized screening test for Down Syndrome (see FAQ‘s).