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    20 week ultrasound
    19 - 21 weeks
    The 20 week ultrasound is an extensive medical ultrasound between 19 and 21 weeks where possible congenital abnormalities are examined.
    45 min
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    What is a 20 week ultrasound

    The 20 week ultrasound is an extensive medical ultrasound between 19 and 21 weeks where possible congenital abnormalities are examined. Fortunately these are uncommon and most babies are born healthy. 

    The 20 week ultrasound is also known as the anomaly ultrasound. The purpose of this ultrasound is to examine if the baby may have an open back and/or skull or any abnormalities of other organs, such as the brain, face, heart, stomach, bowels, kidneys, bladder or limbs. In addition checks are performed on the baby’s growth, the amount of amniotic fluid and the position of the placenta. The 20 week ultrasound cannot identify all abnormalities. Which means the 20 week ultrasound does not guarantee a healthy baby.

    Who is the ultrasound for

    The 20 week ultrasound is especially for pregnant women who do not show an increased risk of their baby developing congenital abnormalities. If family history shows a genetic abnormality, it may be the case that the 20 week ultrasound will be performed at the hospital under the care of a gynaecologist. This is called Advanced Ultrasound Examination (GUO). Your midwife will discuss with you beforehand if you should make an appointment for either a 20 week ultrasound or a GUO. The option to undergo either the 20 week ultrasound or the GUO is always a choice to be made by the expectant parents.


    The 20 week ultrasound results will be discussed with you immediately. Should the sonographer detect an abnormality or have reason for concern, they will pass this information on to your midwife. Your midwife (if you wish) can then arrange a consultation with a gynaecologist.  The follow up examination consists of an extensive ultrasound at a specialist hospital where your baby will be screened further. In some cases the examination will show that there are no reasons for concern after all. Occasionally you will be given the option of having an amniotic fluid test (also called Amniocentesis) in order to exclude genetic defects. During each follow up examination it is your own decision to have this test and what to do with the results.

    Your baby’s sex

    The 20 week ultrasound is a medical examination. This means that sexing the baby is not the main goal of this ultrasound. Should you wish to know the sex of your baby, please ask the sonographer. If it is impossible to determine the sex during this ultrasound (because the images of the baby are unclear), then this is not a valid reason to repeat the 20 week ultrasound. You do however have the option to request a specific ultrasound at Focus Midwifery Centre, especially for determining the sex of your baby. This is called a ‘sex determination’ ultrasound.

    Extra information

    For more information about the 20 week ultrasound and that you may prepare for this examination we recommend that you read the brochure ‘Information about the 20 week ultrasound’. This brochure will be given to you by the midwife or you can download it here The 13-week scan and the 20-week scan (English)

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