Do dating scans date from conception
The dating scan will also show if you're expecting twins, triplets or more.
It's helpful to know about twins early on, as it's easier to see whether or not they share a placenta.
The dating scan will take between five minutes and 10 minutes.
For most mums-to-be, the first scan will be a dating scan at between 10 weeks and 13 weeks plus six days of pregnancy.
However, the timing of your first scan will also depend on how your pregnancy is going, and where you live.
However, some major problems can be seen at your dating scan, such as problems with your abdominal wall or with your baby's skull.
You may need a second scan to check the first scan's findings.