If you are in the majority of women wanting to check for chance of chromosome problems such as Down syndrome as well as structures, 12+ weeks is considered the most accurate time for the ultrasound. If you need further information, an information page is provided about Down Syndrome.

Even parents who do not want chromosome screening or plan to have NIPT (Non-Invasive Prenatal Test), the late first trimester screening ultrasound is still recommended since many of the important checks and findings at this stage are not related to chromosome problems.

It is important to know this 12 weeks pregnant ultrasound varies greatly in detail, for reasons to do with both the fetus and the mother.  A few days’ gestational age can make a big difference to how much detail can be obtained.

When you book this ultrasound, you may be asked whether you have already had a dating ultrasound and if you are having NIPT. This is so we can optimise the timing of the appointment.  

Currently, there is research around the world about the 12-week scan also covering pregnancy complications, such as risk of preeclampsia. Despite some positive publicity, this is not yet a reliable role for first trimester screening across the population.