Antenatal Screening
Combined Screening for Down's syndrome & other chromosomal abnormalities: nuchal translucency scan & blood test (low chance)
All pregnant women in England are offered tests for Down’s syndrome. The tests can provide information about the chance of a baby having Down’s syndrome. These tests use blood samples taken from the mother, measurements taken from ultrasound scans (nuchal translucency scan/dating scan) or both to work out this chance.
The NHS Fetal Anomaly Screening Programme recommends that women have the combined screening for Down’s syndrome (blood test and nuchal translucency scan) rather than just the blood test or the nuchal translucency scan on its own. The vast majority of units in England, Scotland and Wales now offer combined screening for Down’s syndrome.
Nuchal translucency scans (ultrasound) are normally done between 10- 14 weeks of pregnancy. They measure a small fluid collection within the skin at the back of the baby's neck (nuchal translucency) to help identify the chance of Down's syndrome and other conditions. The results are combined with a blood test result (combined screening test) to give a more accurate calculation but these tests cannot give a definite diagnosis.
If the chance is more than 1 in 150, further tests for Down's syndrome will be offered. If the measurement of the fluid is the same or greater than 3.5mm, women will be advised that this may be an indicator of heart or other problems and a referral to fetal medicine specialists will be offered.
The chance of a baby having Down's syndrome increases as the mother gets older. The combined screening test assesses your individual probability, and can show whether it is higher or lower than for other women of the same age.
Not everyone we talked to had a nuchal scan. Sometimes it was not offered locally on the NHS, and some people decided they did not want to pay for it privately, particularly if they felt they had a lower chance of their baby having a condition.
One woman chose not to pay privately because she did not get much information until her booking visit and did not feel she really wanted it. (See also 'Information for making decisions about antenatal screening').
Some people were unsure whether they’d had a nuchal scan or just a dating scan. Many were unaware they could have a blood test at the same time. Some commented that the process seemed very rushed, even if they were well-informed. Two people said that they had made their appointment too late for the scan measurements to be reliable.
For women who book too late (after 14 weeks +1 day), for a combined test (blood test and nuchal translucency scan), the quadruple test is offered. (See ‘Blood test screening’ for more information).
She had the combined nuchal scan and blood test privately, but found out only just in time that...
She had the combined nuchal scan and blood test privately, but found out only just in time that...
So you had to pay for that?
I had to pay for that.
And what was the experience of having that scan like?
It was actually quite rushed in terms of getting it, getting all the different stages done in time. I'm, you know, I'm pleased that she told me about it then, because I could otherwise have missed the window of opportunity.
Almost straight away I had to phone up the centre that do the test, the blood test. They have to send you a sample bottle. You then have to arrange an appointment with your GP nurse to get a blood sample, and send it back to them. And in fact I actually found it quite difficult just to get an appointment with my nurse, so it was all rather tight in terms of time.
For most women who had the nuchal scan, like other scans, it was an enjoyable experience. Many were impressed at how staff took time to explain what they were seeing on the screen and answered questions. The scan gave them their first chance to see the baby, and made pregnancy seem real. This woman also commented on the high quality of the equipment used for nuchal scans at specialist centres. Some women mentioned the discomfort of waiting with a full bladder, and staff pressing uncomfortably hard as they do the scan.
They were impressed by the professionalism of staff carrying out their nuchal scan and felt well...
They were impressed by the professionalism of staff carrying out their nuchal scan and felt well...
The experience was excellent, very straightforward, we had a good feeling afterwards, we felt very reassured with the whole thing, so it's not that I have doubts that, oh, they were, you know, perhaps they didn't know what they were doing.
Seeing her baby during the nuchal scan was a wonderful experience which made pregnancy seem real.
Seeing her baby during the nuchal scan was a wonderful experience which made pregnancy seem real.
It's the best scan, I think, that you really see your baby. I mean, a) it's the first one. Oh, I mean, also I'd been told drink a lot of fluid beforehand, and when she looked at it the first time, the very first scan I had, she was just seeing fluid and fluid and fluid, because I hadn't gone to the loo. I was busting and I'd drunk, like it said on the literature, I'd drunk two litres or whatever, two pints, a litre.
And she - I thought, 'Oh, maybe it's a phantom pregnancy. Maybe it's not really there, you know. Maybe it's just my hormones, you know.' And you know, it happens. And then when she'd actually found it, 'Oh okay. I am pregnant. This isn't just a phantom issue, you know.'
So that was just a bit of relief, really, just to see, to see him there, you know, see he really existed and was happening. And no, I did enjoy it. It was lovely to see both. No, definitely, it was still lovely to see them. I did have this issue I was trying to hold myself back a bit emotionally from getting too carried away until I got the all clear. But I definitely still enjoyed my first sight of them.
In most cases, people were reassured by their results (see also 'Understanding antenatal screening test results'), but some felt anxious during the scan itself. Reasons for worrying included:
- Staff talking to each other, not to the parents
- Calling in a senior colleague without explaining why
- Staff seeming rushed or detached
- Having to have a repeat scan
- Staff keeping or becoming silent without explaining why.
Most people said they preferred to be talked to throughout the scan and have everything explained. (however sometimes the person doing the scan may not feel qualified to discuss the results). A woman carrying twins described different levels of communication in two repeat scans and their effect on her.
In two repeat nuchal scans, she felt the consultant was much more communicative than the first...
In two repeat nuchal scans, she felt the consultant was much more communicative than the first...
Yes. We, I saw the consultant and we had, it was quite a contrast actually, because first of all there was a, I don't know, I think it was a doctor, who did the scan, who had a manner of doing it which was just to sit there sort of silently looking at everything and recording all the information. And the information would be passed on to someone else who was writing it down, it was a nurse or a midwife.
And that was very, quite anxiety-making, because we didn't know what was going on and we did ask, 'What's your measure? What does that measure?', and she'd say, 'It measures the circumference of the head', and they were looking and this and they were looking at that. But we had to ask her and, so she wasn't forthcoming at all in terms of what she thought until she got right to the end when she said, 'I think everything's fine'. But by which stage we didn't believe her because, oh, you know, she hadn't explained anything.
And then, what happened then was the consultant came in, and he went through the whole process again but in a completely different way, which was to describe everything that he saw. And first of all, without going, he just looked at where the babies were lying, where they were and described them.
Then every measurement he did he would say what it was and say, 'That's absolutely fine and there's nothing wrong with the baby'. And his way of dealing with the fact that one of them was curled up, the one was, he was still curled up, was I was lying on the bed and [name], my partner, was sitting on a chair. And he said, 'Well, you're lying down and he's sitting up, what's the big deal?' And basically that's what the babies were like.
The little girl one was lying flat and she could be easily measured, and the other one was like that with his legs over his head. But he said that it was absolutely fine. So his method of explaining what was going on was really substantially better than how the first doctor had done it, and he was really excellent, because you knew exactly what he was seeing, and he was telling you whether there was anything problematic about that and saying that there wasn't. And that was excellent, he was really good.
Had they forewarned you that somebody would come in again and do the whole thing through from scratch?
No, that was really nerve-wracking in that, especially because of how she'd been, and I think I said, 'Why, are you getting the consultant? Did you have to get the consultant in?', or something like that. And she said, 'Oh no, he was going to do it anyway. He was always going to look at the results'.
But they hadn't explained that, so he just kind of appeared from nowhere. And that, having not felt very confident about what had happened so far, that was even more alarming, that they then thought, 'Oh, she needs to get the consultant in.' But in fact he was, he was so good that very shortly after, you know, you began to feel reassured.
And he just had a very much more open and it, just more forthcoming in terms of what was going on and what he was doing, and he had a good way of explaining what he was doing, putting you at ease. He was very good.
One person felt she would probably rather receive bad news after the scan than during it. The importance of human warmth was emphasised by a woman who trained as a doctor, as a message for all professionals communicating with pregnant women, in scans and in other settings.
The sonographer was quiet during her nuchal scan. She would rather wait till after the scan to...
The sonographer was quiet during her nuchal scan. She would rather wait till after the scan to...
And then they're very quiet throughout the whole process. They don't sort of give you any hints as to whether things are good or bad, and then they take you to a little room afterwards and give you a piece of paper which shows you your risk. And I think for my age, which is, will be thirty five when my baby's born, it's about one in four hundred is the sort of national average. And she came back with a piece of paper saying that mine was one in eleven thousand, which felt very reassuring.
What was it like during the scan then, given this silence? Was that worrying?
I mean they pointed out sort of features on the baby, but they didn't give any hint as to whether there were sort of things wrong or not.
Would you have liked them to?
I'm not sure. Possibly. I suppose if it had been good news it would have been nice if they were saying as they were going along, "Well, that looks fine, that looks fine". If it had been bad news I'd probably rather not have known in that position, I'd probably rather be sitting in a room, and sort of take it on board then. But yes, thinking about it, it would have been reassuring if they'd said, "Oh, that looks, that looks good, that looks OK."
She felt it was important for health staff to imagine themselves in the patient's place and...
She felt it was important for health staff to imagine themselves in the patient's place and...
I think it's very, very, very important for everybody who works in health care, whatever you do, to always remember that you have a person there, and that, you know, the fact that you know a bit more in that particular area doesn't make you superior or better to that other person.
And you yourself one day will be in that person's place, because one day you will be a patient, one way or another. So I think we should always keep in mind that, and try to, before putting all the science in practice and all the knowledge, put the humanity, yeah?
And that's what I try to do in everything I do, because I think it's very important to, you know, show some warmth, human feeling to others - and it usually works. So, especially, you know, in the pregnancy experience, which is something so human, so common, so everyday, and which should be always an issue of happiness, and, you know, expectations and optimism.
Yes, healthcare professionals can do a lot just by, you know - I think they do it great here, I am not criticising. I think from what I have seen, people are really great. Nurses and midwives and doctors, they usually are very good.
It is just that sometimes, perhaps for over work, overload of work, or problems of limitations of funds, or whatever, they tend to, you know, be a bit stressed and forget a bit that, you know, that's not only one patient in front of the long queue but a person. So it would be nice to remind them a bit and to make that experience even better.
Some people who were reassured by their nuchal scan results later found their baby did have a chromosomal condition, and some people were told they did have an increased chance of something being wrong with the baby.
(See also 'Combined screening for Down's syndrome and other chromosomal abnormalities: nucal scan and blood tests (being told something may be wrong)', 'Understanding antenatal screening test results', 'Deciding whether to have further diagnostic tests' and 'Learning after birth that the baby has a condition').
Many experiences discussed here are common to other types of scan. (See also 'Early dating scans' and '18-20 week scans' ).
Last reviewed July 2017.
Last updated July 2017.
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