3rd Trimester Obstetric Ultrasound Scans Fetal Growth Assessment

Patient Experience

  • Reference Number: HEY1229/2021
  • Departments: Maternity Services, Ultrasound Department
  • Last Updated: 20 May 2021


This leaflet has been produced to give you general information about your examination. Most of your questions should have been answered by this leaflet.  It is not intended to replace the discussion between you and your midwife of doctor. If after reading it you have any concerns or require further explanation, please discuss this with a member of the health care team.

At your appointment you and the person accompanying you will be asked to wear a mask. If either of you are exempt from wearing a mask you will be asked to wear a face shield. If you do not have these we can provide you with them. If you refuse to wear either of these items we will not perform your scan. We ask this to keep ourselves, you and the people that we encounter after you, safe. 

What is a growth scan?

Some women have extra scans offered to them later in their pregnancy to check their baby is growing correctly. If you have been offered one or more scans.  These are commonly required due to one of the following reasons:

  • You have had a previous small birthweight baby
  • You are a smoker
  • You have a body mass index (BMI) of over 35

There can be other reasons for these extra scans. If you do not fall in to one of the categories above, the reasons for you needing extra scans will be discussed with you by the midwife or doctor looking after you.

When will I have these scans?

The timing of your growth scan will depend on how high risk your pregnancy is considered to be. We understand that having additional scans may cause anxiety and if you do not want to have them you can decline to have these scans. However, these scans are performed so that we can detect any abnormalities before they become problematic to you or your baby.

  • High risk pregnancy. If your pregnancy is considered to be higher risk you will be offered additional scans during the third trimester of your pregnancy. These will be performed at 28, 31, 34, 37 and 40-weeks’ gestation.
  • Moderate risk pregnancy. If your pregnancy is considered to be at moderate risk you will be offered 3 additional scans during the third trimester at 32, 36 and 40 weeks.
  • Moderate-low risk pregnancy

If your pregnancy is considered to be at a slightly raised risk you will be offered 2 additional scans in the third trimester at 32 and 36 weeks.

The appointments will be sent to you through the post. If you cannot attend please ensure you contact the ultrasound department to rearrange as early as you can. It is important that you attend your appointment as arranged but if this is not convenient the appointment can be made available for someone else.

What happens after my gap scan?

Once your baby has been measured the sonographer will plot your baby’s growth on a chart in your notes. If your baby is growing normally you will be able to go home.

If the sonographer or doctor has any concerns regarding the growth of your baby or the blood flow to your baby, the sonographer will send you directly to the Antenatal Day Unit (ADU). This will allow you and your baby’s care needs to be assessed and planned.

Please be aware that the ADU is extremely busy and if you are referred to see them you may have a waiting time of up to three hours or more in exceptionally busy times.

Can anyone come with me for my scan?

We do appreciate that this is a special time for you and your family, however we need to be able to concentrate. All scans require a lot of concentration from the sonographer or doctor performing the test. Distractions from children and multiple people in the scan room could cause them to miss important findings during the scan.

Therefore, you may bring only one other person to accompany you to your scan. No children are allowed into the scan room. We do not provide any childcare facilities. If you bring children to the appointment and they are unable to wait outside then your scan will be re-arranged. To avoid disappointment for your family, friends and children please do not bring more than one person with you to the hospital. They will not be able to sit and watch the examination.

We do not provide any childcare facilities. If you bring children to the appointment and they are unable to wait outside then your scan will be re-arranged.

The waiting area is small with limited capacity for social distancing.  You and the person accompanying you may be asked to wait in the canteen, or outside of the hospital, until we have space in the waiting area. If this is the case, please do not be offended, we want to ensure the safety of you, your baby and others around you. 

Can I buy photographs of my scans?

No. These extra scans are for measuring your baby and for reassurance. We do not offer photographs after your 18 – 20+6-week anomaly scan. Photographs will not be available for you to purchase at any of these extra scans.

Do you have trainees in the department?

The Trust is a teaching hospital and training in ultrasound scanning is supported. A trainee may undertake your examination but they will be supervised or the scan will be checked by a qualified member of staff before you leave the department. You can decline a trainee performing your scan if you wish.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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