A first pregnancy scan – also known as a dating scan or 12-week scan – is an ultrasound scan that is performed at any time between 11 and 14 weeks of pregnancy. It is performed to check how far into the pregnancy you are and to determine that your baby is developing healthily.

Feeling a little nervous about your first pregnancy scan is completely normal, we’re here to help with this extensive article on what to expect. Discover what your first scan entails, what you can to do prepare for you scan and how to get help from our consultants, to put your mind at ease.

When do you have your first pregnancy scan?

The first pregnancy scan usually takes place at around 11-14 weeks of pregnancy, although this can vary. A scan may be done before ten weeks in certain circumstances, including:

  • when there are signs of an ectopic pregnancy or threatened miscarriage such as unusual pain or bleeding
  • if you had assisted conception
  • if you have previously had problems in pregnancy
  • if you have problems such as abdominal pain or vaginal bleeding

How many scans during pregnancy are there?

You will normally be offered two scans during pregnancy; the second one usually takes place between 19 to 21 weeks. In other instances, you may have more scans, especially if your consultant is concerned about your baby’s development.

Why have an ultrasound scan?

“You do not have to have a first pregnancy scan, but it is recommended. It is a non-invasive test that isn’t harmful to you or your baby.” explains Dr Srividhya Sankaran, consultant in maternal-fetal medicine and obstetrics.  A first pregnancy scan is done:

  • to detect your baby’s heartbeat
  • to estimate how many weeks pregnant you are
  • to check for certain conditions, including chromosomal conditions (these are conditions caused by changes in the
  • chromosomes, the DNA molecules that contain the genetic material of an organism)
  • to allow you to find out if you will be having more than one baby

You will usually be told the result of an ultrasound scan a few minutes after it has been carried out.

The first pregnancy scan procedure

All of our pregnancy scans are consultant-led, providing you with access to experienced experts that offer an unparalleled service when it comes to the care of you and your baby. Our highly qualified obstetric consultants are trained in maternal and fetal medicine and will be with you every step of the way.

The procedure usually takes place at our hospital’s ultrasound department or at Wimpole Street diagnostic and outpatient centre. Your consultant can show you colour images of your baby using the most advanced 3D and 4D imaging techniques.

During the procedure, you will be asked to lie on your back to reveal your lower abdomen so that the ultrasound gel may be applied. The gel ensures there is contact between your skin and the ultrasound probe (a small device that gives off harmless high-frequency sound waves).

The probe will be placed on your tummy, producing an image of your baby which will be shown on the ultrasound screen. Your baby’s body can then be examined by the consultant.

The results of your scan will be explained to you clearly by the consultant, giving you peace of mind that the care of you and your baby is in good hands. In the event that an abnormality exists, your consultant can provide advice and counselling regarding further management, including consulting with other specialists as necessary.

How long does a first pregnancy scan take?

A first pregnancy scan usually takes 20 to 30 minutes. It can take longer if your baby is moving around, or lying in a position that makes it hard to get the required views.

You may also choose to have a Down’s syndrome screening test at the same time as your first pregnancy scan.

Down’s syndrome screening

During the first pregnancy scan, mothers will usually be offered a combined test to assess their chances of having a baby with Down’s syndrome.

This is called the Down’s syndrome screening test, and its results can indicate the chances of you having a baby with Down’s syndrome. It also tests for Edward’s syndrome and Patau’s syndrome.

In the Down’s syndrome screening test, a blood sample is taken and the nuchal translucency – that is, the thickness of the fluid which is found in the back of a baby’s neck – is measured. Babies with Down’s syndrome or some of the other abnormalities may have more fluid.

How to prepare for your first pregnancy scan

There are several steps you can take to prepare for your first pregnancy scan. You should have a full bladder for the ultrasound examination because the fluid enhances sound waves moving through the abdominal cavity.  Empty your bladder 90 minutes before the test, and then consume a 300 ml glass of fluid (it could be water, milk or a hot drink) around an hour before the exam.

It is also recommended that you wear a two-piece outfit, to provide access to your abdomen more easily. Eating before a pregnancy ultrasound is usually fine.

What other tests may be offered in the first pregnancy scan?

A test called ‘Harmony test’ or NIPT (non-invasive prenatal testing) may be done, as this test is superior to the combined screening test in detecting Down’s syndrome.  This test detects fetal DNA in your blood and reports on the chances of Down’s syndrome. This test may be arranged on request.

What happens after? (an anomaly scan)

The second and final scan that you are offered between 19 and 22 weeks is called the anomaly scan or 20-week scan. This is a detailed ultrasound scan that is offered to everybody. It checks how your baby is developing structurally – you can also find out the baby’s gender.

Private pregnancy scans and maternity care in London

At Guy’s And St Thomas’ Private Healthcare we provide scans at all stages of pregnancy and options to choose from our growth surveillance or complete scanning packages to give you peace of mind.

Our expert obstetric consultants, Dr Srividhya Sankaran and Mr Spyros Bakalis, who are sub-speciality trained in maternal and fetal medicine, offer scanning services ensuring the care you and your baby get is of the highest standard.

With access to maternity and children’s services on the same site at St Thomas’, we are in a unique position to provide care for you and your baby at every stage of life, all at one location.

For more information on our private maternity services or to book a scan, contact our specialist team.