12-week pregnancy dating scan: what will it tell me?

"I had my 1st scan today," says Jodig in a post on our Chat forum, "and I cannot believe how long my baby's legs are! So in love, it's unreal!"

What does a 12-week scan reveal?

Officially, the purpose of the scan is to check:

When your baby is due. An ultrasound scan is a much more accurate way of predicting your baby's gestation (how far along in the pregnancy you actually are) than counting from the date of your last period (which is all you and your GP have had to go on up till now).
Whether you're having twins, triplets or more. Yep, this is the moment when you find out if there's more than 1 baby in there!
Whether there's a heartbeat and if the skull, limbs, organs, and umbilical cord are developing normally. This is the bit that, naturally, we all worry about.
What the position of the placenta is, and how it's developing.
Your baby's NT or nuchal translucency. This is a part of your scan that you can opt out of but, combined with a blood test, this measurement of the fluid at the back of your baby's neck can give you an indication of your baby's chance of Down's syndrome, Edwards' syndrome and Patau's syndrome.

In other words, as squeak185 sums it up: "They will basically check that there is a heartbeat and that the baby is measuring the right size for how far along you think you are. They will also check that anatomically everything is where should be. Then you get your amazing pictures and you can tell the world!"

Will I have the scan at exactly 12 weeks into my pregnancy?

Not necessarily. Dating scans are offered at some point between 8 and 14 weeks, with most of them happening between 11 and 14 weeks.

If you've had fertility treatment, have a history of miscarriages or are in pain or bleeding during the first weeks of pregnancy, you may be offered an early scan before this routine dating scan. But, assuming your pregnancy is healthy, you'll still have the dating scan at round about the 12-week mark.

What happens at the scan?

The scan is done externally by rolling a device over your tummy (unless your womb is very deep in your pelvis or you're very overweight, when it may be thought better to offer you a trans-vaginal scan instead).

You'll be asked to arrive with a full bladder. This is because, as immense explains, "If you drink lots of water beforehand, you get better pics: it pushes the uterus (womb) closer to the surface!"

The scan itself will take about 15 to 30 minutes but you may need to hang about for a while in the waiting room beforehand – which can be tricky when you've just drunk all that water!

But don't be tempted to skip the water drinking for that reason. As ttc princess posted in our forum, if you're bursting, "they can always send you for a [bit of a] wee but, if your bladder's not full enough, they might send you home".

It's best to wear trousers or a skirt and a top, rather than a dress, as once you're in the (dimly lit) room, you'll be asked to lie on your back on a couch and adjust your clothes to expose your bump.

Then the sonographer will put some gel on the skin of your tummy (be ready: it’s normally freezing!) so there is good contact between the transducer (the hand-held scanning device) and your skin.

Once the gel's on, the sonographer will place the transducer – which looks a bit like a computer mouse or a small paint roller – onto your bump and move it around, allowing the high-frequency sound waves produced by the transducer to bounce off your belly and create a picture on the sonographer's monitor.

More like this

It doesn't hurt at all but you'll probably feel some downward pressure (which can be a wee bit uncomfortable on a very full bladder).

As the transducer gets to work, a black-and-white image of your baby will appear on the monitor that the sonographer is looking at. Often, you can see the screen too, or it'll be turned towards you after a few moments – but not always.

"Sonographers have a lot to do in a short amount of time, so they need to keep the screen in a position that gives them the best view of the baby,” explains Nigel Thomson, professional officer for ultrasound at the Society and College of Radiographers. “Hopefully, you will see, too, but you need to remember that the points of this clinical examination to check everything is OK with your baby.

"All being well, you're likely to see your baby moving around. And, if the pregnancy is progressing well, you'll also see a clear heartbeat."

MFM forum user BL Rosie found seeing those first images overwhelmingly joyful. “It was AMAZING!" she says."The baby was so active, stretching and kicking."

You’re not usually allowed to take your own video or photos whilst in the scan room but most NHS hospitals will let you take away a photograph of the scan image once your appointment has ended. Costs for these vary, and aren't always flagged up in advance, so do make sure you take some cash with you.

(If you’re after lots of glossy colour pics or maybe even a video, you can book a private scan but it's best to wait till you're at least 16 weeks pregnant, when there's much more 'baby detail' to see.)

Should I take my partner to the scan?

Your partner (or another close relative) will always be welcome to come with you but it's totally up to you, of course. Most mums-to-be would probably say it's a good idea to have some company, especially if you're anxious about the scan.

"Having a scan can be very emotional," says Jane Fisher, director of the testing-support charity Antenatal Results and Choices (ARC). "You may need someone there to support you."

Can I take my other children to the scan?

You’ll need to check with your hospital about this one, and you should be prepared for them to say no – quite a few hospitals don't allow small children into the pregnancy ultrasound departments.

"The policy on children can be very variable," says Nigel. "Performing the scan requires intense concentration from the sonographer, so [many hospitals take the view that] the fewer distractions, the better."

Will I be able to tell from the scan if my baby's a boy or a girl?

"The policy at most NHS trusts is not to give an opinion at this scan," says Nigel. "That's usually only offered at the anomaly scan [your 2nd routine scan, done at about 20 weeks]. Private providers may offer this earlier, however.”

If you fancy having fun predicting your baby's sex yourself, there are several theories you can try out once you have your 12-week scan photo. These include the nub theory, the skull theory and the 3 lines theory.

Will I get the results straightaway?

Pretty much – even if it's not such good news.

"If there is clearly an issue with the scan, then you will be told that day," says Nigel. "And you’ll probably be referred straight on to a specialist to help you make decisions about further tests.”

The only exception to the results-straightaway rule is, sometimes, the result of the combined testing for Down’s syndrome, Edwards' syndrome and Patau's syndrome (if you consent to it).

In order to get the full results, the findings of the nuchal translucency (NT) part of your scan need to be combined with the findings of your blood test. If you haven't had your blood test yet (timings of these tests do vary from hospital to hospital) or if your blood test results haven't come through in time for both results to be combined into the final result, you'll have to wait to get this result from your midwife at a later date (do ask when that's likely to be).

What will the results tell me?

If all is well and your pregnancy is progressing as it should – which is the case about 95% of the time – you will be given your official due date, or estimated date of delivery (EDD), and told exactly how pregnant you are.

You may find that your EDD is quite a few days later or earlier than you thought. "I was what I thought was 11 weeks, 6 days when I went [for my scan]," says squeak185, "but they moved my dates back by 5 days as the baby was a bit smaller."

You'll also be told whether you're having twins, triplets (or more) – though you'll probably have noticed that already on the scan monitor!

If your scan picks up anything of concern, this might include:

Missed miscarriage. Very occasionally (in about 1% of pregnancies), the sonographer may not be able to detect the baby's heartbeat. This is usually because, earlier on in your pregnancy, the baby died, or failed to develop, but you may not have had any signs or symptoms (like pain or bleeding). If this happens to you, there are a number of possible next steps; you will be given specialist advice – and time to make up your mind.
A developmental concern. Sometimes, the sonographer will detect an abnormality which may indicate a problem with your baby's development. If this happens to you, you will be referred to a fetal medicine consultant for further advice and tests.
Low-lying placenta. This is usually not treated as an urgent concern. It will be probably just be noted on your file, and checked carefully later at your 20 week scan.
A raised NT score. You may be told on that day if your nuchal translucency test scored higher than 3.5mm. "This raised NT can sometimes be an indicator of a problem in the baby's development," explains ARC's Jane Fisher. But it needs to be looked at in combination with your blood test. If, when that is done, "you will," says Jane, "be offered an appointment with a consultant to discuss the possible implications." Which may include further tests, including NIPT, amniocentesis or CVS. "Although this can be worrying," says Jane, "it is important to remember that many babies whose NT measurement is higher than average do develop normally.”

I'm so worried about this scan? Should I be?

Of course, you're anxious (as well as excited at the idea of seeing your baby). We all are! But it really does help to try to keep things in perspective: the chances of anything being 'wrong' with your baby are very small.

“While it’s good to be prepared, be reassured that there is only an issue in around 3 to 5% of scans,” says Jane.

Even if there is an issue, it may well be something that turns out to be not that serious or something that can be easily managed by the specialists.

And there's always a follow-up with support and advice. “If there is a problem, you will be supported and referred to a specialist," says Jane. You can also call the trained staff on the ARC helpline (Monday to Friday, 10am to 5.30pm) on 0845 077 2290 (or 0207 713 7486 from a mobile.)

But, above all else, remember that, for at least 95% of us, the scan will be fine and we'll go home clutching that amazing (and slightly tear-stained) first pic.

As forum poster kew25 says, "I was so worried. I was literally having an asthma attack by the time they called me in. But it was great. I saw his little heartbeat (I now think it is a boy!) and he was bouncing up and down and kicking his arms and legs! It really was great – hubby even welled up!"

Rachel Mostyn