Pregnancy and baby

Ultrasound scans in pregnancy

What happens at a scan and what will they tell me?

Media last reviewed: 20/03/2014

Next review due: 20/03/2016

Ultrasound scans

Ultrasound scans use sound waves to build a picture of the baby in the womb. The scans are completely painless, have no known side effects on mothers or babies, and can be carried out at any stage of pregnancy. Talk to your midwife, GP or obstetrician about any concerns you have.

For many women, ultrasound scans are the highlight of pregnancy. It's very exciting to "see" your baby in the womb, often moving his or her hands and legs.

Having a scan in pregnancy is usually a happy event, but be aware that ultrasound scans may detect some serious abnormalities, so you should be prepared for that information.

See What if a screening test shows a possible problem? for more information on what may happen if a scan or other screening test suggests an abnormality.

What will happen in the scan room?

Most scans are carried out by specially trained staff called sonographers. The procedure is carried out in a dimly lit room so the sonographer is able to get good images of your baby. You will first be asked to lie on a couch. You will then be asked to lower your skirt or trousers to your hips and raise your top to your chest.

The sonographer will put ultrasound gel on your tummy and tuck tissue paper around your clothing to protect it from the gel. The gel makes sure there is good contact between the machine and your skin.

The sonographer passes a handheld device called a probe over your skin. It is this probe that sends out ultrasound waves and picks them up when they bounce back.

A black and white picture of the baby will appear on the ultrasound screen. During the examination, sonographers need to keep the screen in a position that gives them a good view of the baby – either directly facing them or at an angle.

The sonographer will carefully examine your baby's body. Having the scan does not hurt, but the sonographer may need to apply slight pressure to get the best views of the baby.

How long will a scan take?

A scan usually takes around 20 minutes. However, the sonographer may not be able to get good views if your baby is lying in an awkward position or moving around a lot.

If you are overweight or your body tissue is dense, sometimes this can reduce the quality of the image because there is more tissue for the ultrasound waves to get through before they reach the baby. If it is difficult to get a good image, the scan may take longer or have to be repeated at another time.

Can an ultrasound scan harm me or my baby?

There are no known risks to the baby or the mother from having an ultrasound scan, but it is important that you consider carefully whether to have the scan or not.

The scan can provide information that may mean you have to make further important decisions. For example, you may be offered further tests that have a risk of miscarriage.

When will scans be offered?  

Hospitals offer all pregnant women at least two ultrasound scans during their pregnancy:

  • at 8 to 14 weeks, and
  • between 18 and 21 weeks

The first scan is sometimes called the dating scan. The sonographer estimates when your baby is due (the estimated date of delivery, or EDD) based on the baby's measurements.

The dating scan can include a nuchal translucency (NT) scan, which is part of the combined screening test for Down's syndrome.

The second scan offered to all pregnant women is called the anomaly scan, or mid-pregnancy scan, and usually takes place between 18 and 21 weeks of pregnancy. This scan checks for structural abnormalities (anomalies) in the baby.

Some women may be offered more than two scans, depending on their health and their pregnancy. You can find out more about the dating scan and the anomaly or mid-pregnancy scan.

When will I get the results?

The sonographer will be able to tell you the results of the scan at the time.

Do I have to have ultrasound scans?

No, not if you don't want to. Some people want to find out if their baby has problems, while others don't. The dating scan and anomaly scan are offered to all women, but you don't have to accept them.

Your choice will be respected if you decide not to have the scans, and your antenatal care will continue as normal. You'll be given the chance to discuss it with your maternity team before making your decision.

What can an ultrasound scan be used for?

An ultrasound scan can be used to:

  • check your baby's size  at the dating scan, this gives a better idea of how many weeks pregnant you are; your due date, which is originally calculated from the first day of your last period, will be adjusted according to the ultrasound measurements
  • check whether you're having more than one baby
  • detect some abnormalities
  • show the position of your baby and the placenta  for example, when the placenta is low down in late pregnancy, a caesarean section may be advised
  • check that the baby is growing normally  this is particularly important if you're carrying twins, or you have had problems in this pregnancy or a previous pregnancy

Can I bring family or friends with me when I have the scan?

Yes. Ultrasound scans can sometimes find problems with the baby. You may like someone to come with you to the scan appointment.

Most hospitals do not allow children to attend scans as childcare is not usually available. Please ask you hospital about this before your appointment.

Remember, an ultrasound scan is an important medical examination and it is treated in the same way as any other hospital investigation.

If everything appears normal, what happens next?

Most scans show that the baby is developing normally and no problems are found. This is because most babies are healthy and do not have abnormalities.

If the scan finds there might be a problem, what happens next?

If a problem is found or suspected, the sonographer may ask for a second opinion from another member of staff. You might be offered another test to find out for certain if there is a problem.

If you are offered further tests, you will be given more information about them so you can decide whether or not you want to have them. You will be able to discuss this with your midwife or consultant.

If necessary, you will be referred to a specialist, possibly in another hospital.

Is it a girl or a boy?

Finding out the sex of your baby is not offered as part of the national screening programme, but this depends on the policy of your hospital.

If you want to find out the sex of your baby, you can usually do so during the mid-pregnancy scan. Tell the sonographer at the start of the scan that you'd like to know your baby's sex.

Be aware, though, that it's not always possible for the sonographer to be 100% certain about your baby's sex. For example, if your baby is lying in an awkward position, it may be difficult or impossible to tell.

Some hospitals have a policy of not telling patients the sex of their baby. Speak to your sonographer or midwife to find out more.

Can I have a picture of my baby?

You will need to check if your hospital provides this service. If they do, there may be a charge.

Page last reviewed: 25/02/2015

Next review due: 25/02/2017


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The 13 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Jocasta trotter said on 27 May 2015

Right now it's my 21st wek of pregnancy and day before yesterday i had severe head spin. It was so severe that i was unable to even turn postions. It felt like i would drown as i closed my eyes. Next day my position have been same but not very severe. Now i feel heavy head, eyes and dizzy from time to time.
I talked to my doctor but she is not coming to any conclusion what this might be.
Can any one help regarding this?

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Swap15 said on 16 June 2014

I was 12 weeks Pregnant and was very excited for my first scan ....but unfortunately scan revealed that I had an empty Sac with no baby ...they even did an internal scan , but got same results day I was advised to go to Cotswold ward , there I came to know that formation of baby never happened and I only got empty Sac from start was a shock for me and family , as we never heard anything like this before ....I'm going through hell , both emotionally and physically....
I have done two pregnancy test one on 14th May and 24th May, both we're positive....never had any bleeding within all these 12 weeks until first scan is done nothing can be taken for sure.... I'm writing my horrible experience so that other people know how different miscarriage can be ....hope and wish no one go through all this hell....
Both nurse at Southmead antenatal clinic and Cotswold ward are really helpful .....

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Jo082 said on 22 May 2014

I'm 16 weeks pregnant, had a few bleeds, I've had no appointment for 12 week scan, I've paid for private scan to put my mind at rest, not seen a midwife yet..! Also have gestational diabetes with previous pregnancies and have not had no glucose test, a lot has changed since my first baby 15 years ago, but can never fault the care once it's there

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Skye1214 said on 29 April 2014

Does anyone know when you receive your dating scan letter?

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Lau devon said on 28 April 2014

I am 12 weeks pregnant but due to a baby boom in Devon my hospital cannot fit me in for my first scan until I am over 15 weeks pregnant. I thought I should have had it at 12 weeks so am concerned about this delay
Has anyone else had this response?
Will this have repercussions on the ability to date the bay or identify any problems?
I'm worried about the delay but perhaps it is quite normal?

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Fudge89 said on 24 July 2013

I got my appointment through for my ultrasound today. It's quite exciting as it's like an official aknowledgement of the pregnancy and I can't wait!!! My midwife isn't seeing me for the first time until a couple of days before... is this normal? Also, does anyone know the rough price to buy the ultrasound picture? And can you get more than one?

Can't wait!!!!

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Plast said on 11 July 2013

I have been told that its better to get a doctor to do the ultrasound rather than a sonographer, as the sonographer is not able to give advice like a doctor would do. plus they have to send the scan results to the GP.

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muffin86 said on 20 March 2013

're my previous post I found this site very helpful

I am also wondering why I didn't have any blood tests done as it seems that is a good way to check for miscarriage and sometimes more reliable than an ultrasound.

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muffin86 said on 17 March 2013

Why is there nothing on this page or in any of the pregnancy information given out that warns or mentions that you might not see anything in your first ultrasound and what this might mean. I am pregnant for the first time and have just had my first ultrasound. I didn't have periods before I found out I was pregnant due to the contraceptive pill. The midwife has done all my blood tests and all are fine. I went into the scan so excited expecting to be dated at around 11 weeks. I was so upset and disappointed to be told there were two sacs but nothing could be seen growing in either. I was told one is too big not to have anything in, but the other is smaller and still has a chance. I have to wait a week and go back for another scan. My partner and I were devastated and completely unprepared for this news. I had read every bit of info to prepare and inform myself about tests but not heard anything about this. Apparently I might be around 5 weeks pregnant and that's why nothing is visible, or it might be a blighted ovum. I felt so let down by my midwife and the nhs not to have been prepared for this. Everything I now know about it I have read on websites from other women who have been through the same thing. I thought if you had a positive pregnancy test, all the symptoms of pregnancy and no signs of bleeding or abdomen pain then everything must be pretty much ok. Please put something on the sight about the different things an early ultrasound might show and what this might mean. If I had been prepared it would have saved a bit of heartache. I hope any other women and their partners that are going through this find it helps to know they are not alone, and sometimes it can still work out ok. Even if it doesn't it is unlikely you did anything wrong. The egg just might never have been viable. The waiting is the worst part. Stay strong.

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Sab90 said on 14 January 2013

I am 14 weeks and 1 day, its my first pregnancy and still not had no appoinment, I understand I miss my first scan and need to know if its ok as I am worried and dont know nothing, can pple pls help me.

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lmcp1981 said on 08 December 2012

I appologise for my previous comment as I have now realised that it was you yourself that wrote the article. But having a 5 minute skim read of it I have the following comments:

In the Lorenz study the women were given weekely scans, twinty times the amount offered to NHS patients, and the ONLY side effect was preterm labour. Are we talkng a week, two weeks preterm, or more???? You don't make that clear. And may I add that the women recruited to the trial were those that were at risk of pre-term labour anyway!

The numbers in the Helsinki trial are too small to be significant are they not? Were there any other contributing factors to the miscarriages?

You didn't add the Davies trial to your reference list, however again I would question the significance of the small numbers of adverse results.

And the physiotherapist trial is irrelevant! Physios use high frequency therapeutic ultrasound to generate heat in tissues to treat scar tissue, inflammation, swelling etc. It is completely different to diagnostic ultrasound and cannot therefore be compared!

There is no critical appraisal in your article, which is incredibly dangerous in health reasearch. I refer again to the MMR fiasco!


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Susie said on 04 December 2012

Beverley - thank you for your comment. It is important to rely on the best available evidence. A systematic review of the safety of ultrasound in pregnancy was published by the WHO (World Health Organization) in 2009. The conclusion was that according to available evidence, exposure to diagnostic ultrasonography during pregnancy appears to be safe.

The WHO review references 86 studies. Anyone who would like to see the WHO review can do so via this link:

Susie at NHS Choices

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Beverley Beech said on 12 November 2012

Your web site states:
Ultrasound scans use sound waves to build a picture of the baby in the womb. The scans are completely painless, have no known side effects on mother or babies and can be carried out at any stage of pregnancy.
The claim that medical research has found no known side effects of ultrasound is untrue.
Research by Lorenz showed that preterm labour was more than doubled in the ultrasound group; Saari-Kemppainen's research revealed 20 miscarriages after 16-20 weeks in the screened group and none in the controls; Davies research had 16 perinatal deaths of normally formed infants in the Doppler group compared with 4 in the standard care group; Taskinen's research found that if the physiotherapist was pregnant, handling ultrasound equipment for at least 20 hours a week significantly increased her risk of spontaneous abortion and the risk of spontaneous abortions occurring after the tenth week was significantly increased for deep heat therapies given for more than 5 hours a week, and ultrasound more than 10 hours a week.
The above are just a few of the side effects of ultrasound, I could list more, such as the Australian study that found that ultrasound reduced the baby’s weight (rather crucial in a baby considered to be small for dates!)

I trust you will amend the mis-information on your web site and I look forward to hearing from you.
Beverley A Lawrence Beech
Hon Chair
Asociation for Improvements in the Maternity Services

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