Discovering that you might need to have CVS during pregnancy can be a really worrying time. You’re probably feeling very confused and this is a place where you can get lots more information about what is involved and whether or not it is something that you want to go ahead with.


“The most important thing to remember,” says Jane Fisher from ARC, the charity Antenatal Results and choices, “Is that you have a choice as to whether you want to have this test. You will be given advice but ultimately it is your decision.”

The reason you will probably have been offered CVS, which stands for Chorionic Villus Sampling, is because you’ve either had the combined screening test for Down’s, Edwards’ and Patau’s syndrome or NIPT testing and it has said that you are at higher risk of there being a problem with your baby. Usually this is set at between 1 in 2 to 1 in 150 odds of your baby having one of these conditions. You might also be here because you have a family history of a genetic condition or that you have had problems in other pregnancies.

“The CVS will then give you a definitive yes/no answer on Down’s, Edwards’ and Patau’s syndromes and depending on what tests are done on the CVS sample, can also detect other chromosomal syndromes and changes,” explains Jane Fisher.

Clare F from our MadeForMums community explains why she went ahead with the CVS;

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“We had a bad nuchal scan, knew we were likely to be high risk so just had to wait for bloods to confirm [as part of the combined test]. They called next day to say we were 1 in 5 odds. That was the Wednesday and we had an appointment for the Friday for CVS.”

Before we go into more detail about CVS, it can be helpful to think more generally about screening. The NHS suggests imagining it like a sieve. So we’re all invited to have the original screening (in this case either combined screening or NIPT which is probably done privately) which gives us the likelihood of there being a problem. Most of us who go down this route are fine and we pass through the sieve and go on to have a healthy baby. But if you’re one of the ones left in the sieve, it means you are at a higher risk of there being an issue. It’s at this stage you have to start thinking about diagnostic tests which give you a definitive answer. Step forward CVS and amniocentesis.

Community member Natalie A, explains “We were advised to get a CVS because our screening blood work came through as 1 in 70 for Down’s,”

What actually happens?

Firstly CVS is usually done from 11 to 14 weeks of pregnancy. “A fine needle, usually put through your tummy, is used to take a tiny sample of tissue from the placenta. The cells from the tissue are then tested for Down’s syndrome, Edwards and Patau,” explains Jane. “It’s done earlier than an amniocentesis, which happens at around 16 weeks, and some women prefer to find out earlier if there is a chromosomal issue..”


Might I miscarry?

Understandably one of the first things people worry about is the chance of miscarrying. According to the NHS about 1-2%, so one in a 50 or 100 women will have a miscarriage after having CVS. This is slightly higher than an amniocentesis which the NHS estimates is closer to 1%.

“This risk of miscarriage is one of the most frightening things about these tests,” confirms Jane. “There is that small chance that you will have a miscarriage even though your baby is perfectly healthy. For some of you it might be helpful to look at the odds you have been given of an issue being detected versus the miscarriage rate.”

We know that these are not easy decisions. Debbie M from our community shared;

“It is an awful thing to think about, but it's sensible to have an idea beforehand of what you're going to do rather than be put in that horrible situation and then have the emotions adding to it all. We made the decision that if the risk was higher than a certain level then I'd go for further testing (CVS or amnio) - but below that we'd continue.

I do have a friend whose risk was about 1/100, and she really didn't know what to do for the best with the risk of mc being similar if she was to have further tests. She decide not to have further testing although worried throughout the rest of her pregnancy, but her baby was ok in the end. She had a similar thing with her second baby girl as well.”

The NHS does also says that it’s difficult to know which miscarriages would have happened anyway, and which are directly because of CVS. According to NHS choices there is also some recent research which suggests only a tiny number of miscarriages happen as a direct result of the procedure.

If you are going to have a miscarriage it will probably happen within two weeks of the testing. And sadly there isn’t anything you can do during this time to stop it happening. It is an agonising time, And if you’re in this position we really feel for you.

“Actually most of those few women who have a miscarriage due to the procedure have it fairly soon afterwards, within around 72 hours. There is still a risk of miscarriage after this, and for up to two weeks after the CVS, but it is extremely unlikely to happen.” explains Jane.

It’s also worth asking your hospital if they have their own rates on miscarriage and CVS as it can vary from hospital to hospital and this may influence your decision.

For Rebekah S from our community, for example, the miscarriage rate at her hospital was lower.

“We go tomorrow for our CVS, to see if we can continue with the pregnancy or whether we need to terminate, due to a genetic condition within the family.

I just can't bear the thought of having a miscarriage from the procedure tomorrow (low chance - generally 1% risk and only 0.5% risk in this hospital but still a risk) or needing termination in a week's time. It's making me want to hibernate until the results are back.”

“If the healthcare professional performing the procedure is skilled at doing it, this can help to minimise the risk,” explains Jane Fisher. “This skill comes with experience so you can ask how often the doctor who is going to do your CVS does the procedure. The Royal College of Obstetricians and Gynaecologists recommends that a healthcare professional should do at least thirty procedures a year to retain his or her competency,”

What will CVS test for?

CVS will give you a definitive answer as to whether your baby has Down’s syndrome, Edward’s and Patau’s. out more information about the conditions themselves by visiting the Down’s Syndrome Association website and SOFT for Edwards’ and Patau’s. There is also lots of information in the NHS screening programme booklet which your midwife should have given you.

CVS can also test for other conditions such as duchenne muscular dystrophy.

How quickly will the test be arranged?

“As you need to have CVS between 11 and 14 weeks and your combined screening results may only arrive after your 12 week scan, it will probably feel like everything is quite rushed and you need to make a decision quickly,” says Jane.

As Natalie A explains “We agreed on the Sunday and I was seen on Wednesday, so it was really quick”

It’s really important though that you feel you have enough time talking to your partner and family, get advice from your midwife and the doctors and also talk to a charity like ARC if you need. You can call their helpline on 0845 077 2290 or 0207 713 7486 from a mobile.

The appointment itself

Check with your midwife and doctor but you might be asked for a full bladder because it makes the test easier to do.

The doctor will use an ultrasound scan as a guide and then a very thin needle is used to take a tiny sample of tissue from your placenta. The needle is usually put through your tummy but very occasionally your vagina.

The test itself takes about 10 minutes, although the whole consultation may take about 30 minutes. For some of our Mums it can be even longer waiting for your baby to get into position. Ally M from our community explains her experience.

“So they scan you, to check positioning of the baby, my husband was able to see William throughout. They injected local anaesthetic and then took a sample of placenta and that's literally it, They then show you baby afterwards.

It shouldn’t be painful at all but you might feel uncomfortable.

Can you drive after?

Afterwards, you will be monitored for up to an hour, in case the tests have any side effects. such as heavy bleeding. And then you can then go home to rest.

It’s probably best to make sure you have someone to drive you home as you may not feel up to it.

Recovering after CVS

After you’ve had CVS, it's normal to have cramps similar to period pain and light vaginal bleeding called "spotting" for a day or two. You can take over-the-counter painkillers such as paracetamol (but not ibuprofen or aspirin). Again it’s best to check this with the doctors and your midwife

The advice from the experts is to certainly take it easy for a few days after.

That was what Ally M did;

“I was off work anyway, I had some cramps on the Thursday but otherwise I was fine. My husband wanted me to rest though, but I was up and about on the Friday as normal. I was 12+6 I think when I had the CVS.”

When you should get help

The NHS says you should definitely call your midwife or the hospital as soon as possible if you experience any of these symptoms after;

  • persistent or severe pain
    • a high temperature of 38C (100.4F) or more
    • chills or shivering
    • heavy vaginal bleeding
    • discharge of clear fluid from the vagina
    • contractions

When will I get the results?

“My results came back within 48 hours and they gave you a yes or no answer as to whether your baby has Down's, Edward's or Patau's syndrome. They will also tell you the sex of your baby (if you want to know).” explains Joanne W from our community.

As Ali M explains in more detail; “It was Thursday afternoon and the initial Down’s, Edwards’ and Patau’s results came back on the Monday, The doctors said it was unlikely anything else would come back as positive if these were ok. Then 2 weeks later the rest of the results came back, and we asked to find out the sex.

As ever it varies across the country but you can choose whether you get the results over the phone or in a face-to-face meeting.

The other slight issue is that in around 1% of procedures, the sample of cells they take from your placenta may not have been right for testing. This could be because not enough cells were taken, or because the sample has been contaminated with your cells.

Unfortunately this might mean they have to do it again or you wait a few weeks to have an amniocentesis instead.

Next steps

While there are no actual statistics at to how many of you will get a negative result on your CVS, Jane Fisher says, “for the majority of you who do have CVS the results will come back normal.”

For those of you where an issue has been detected, you will be given much more information. Of course then you may well be faced with a very difficult decision as to whether you want to continue with your pregnancy.


As well as talking to your doctors, midwife and your own family, do contact ARC for advice 0845 077 2290 or 0207 713 7486 via mobile