Your 12-week scan: what happens and what it checks

The 12-week scan is often the first time you see your baby. Here’s what happens, what it checks, how to get ready and what screening you’ll be offered.

What is the 12-week scan?

The 12-week scan, also called the dating scan, is an ultrasound scan that the NHS offers at around 10 to 14 weeks of pregnancy in England. Timing can vary between areas and between the UK nations, so your midwife will tell you when yours is booked. It usually takes place at your local hospital’s ultrasound department and takes about 20 minutes.

What does it check?

The NHS says the scan is used to see how far along you are and to check your baby’s development. It looks at:

how many weeks pregnant you are, which is used to work out your estimated due date
whether you’re expecting more than one baby
that your baby is growing in the right place
your baby’s development. The scan can pick up some conditions, such as spina bifida.

Getting ready

You may need a full bladder for the scan, because it makes the image clearer. The NHS suggests asking your midwife or doctor beforehand whether this applies to you, so check your appointment letter.

Screening offered at the scan

If you’ve agreed to it and your scan is between 10 and 14 weeks, you can have screening for Down’s syndrome at the same appointment. The NHS says this uses a blood test plus a measurement of the fluid at the back of your baby’s neck (the nuchal translucency). You’ll also be offered screening for Edwards’ syndrome and Patau’s syndrome.

Screening is your choice. It can tell you the chance of your baby having a condition, but it can’t give a certain answer. If your scan takes place after 14 weeks, the NHS says you’ll be offered a different blood test between 14 and 20 weeks, which is less accurate.

What if something is found?

If the scan or screening suggests something may need a closer look, you’ll be told and offered a chat about what happens next. You can take someone with you and ask for more time to decide. Tommy’s has a midwife helpline on 0800 0147 800 if you want to talk anything over.

Your due date

The NHS says the scan is used to work out your estimated due date. If you’re curious how it relates to when you conceived, see working out your conception date.

Questions people ask

Does the 12-week scan hurt?

A scan isn’t usually painful, but tell the sonographer if you’re uncomfortable.

Do I have to have the screening?

No. It’s offered, and you can say yes or no to each part.

Can I have this scan in Scotland, Wales or Northern Ireland?

The NHS page describes England. In Wales the dating scan is offered at 10 to 14 weeks and the anomaly scan at 18 to 21 weeks. In Scotland, Down’s syndrome screening is offered at about 11 to 14 weeks. In Northern Ireland, your local trust sets the timings. Your midwife will confirm yours.