Determining your Scan Pathway in Pregnancy UtAD screening
Determining Your Scan Pathway in Pregnancy (UtAD Screening)
Patient Information
Maternity Services
- Author ID: SW/DP
- Leaflet Ref: Mat 004
- Version: 2
- Leaflet title: Determining your Scan Pathway in Pregnancy (UtAD screening)
- Last review: December 2022
- Expiry Date: December 2024
Introduction
All women will be offered a dating scan around 12 weeks of pregnancy and Fetal anomaly scan (FAS) around 20 weeks of pregnancy. Please follow the link for further details https://www.gov.uk/government/collections/screening-in-pregnancy-information-leaflets
For the women who we consider to be high risk of having a baby who might not grow to its full potential we can offer a Uterine Artery Doppler (UtAD) ultrasound screen. This leaflet will explain about this in more detail.
Aims
The aim of having UtAD screening is to identify those babies that are at greater risk of not growing to their full potential and the likelihood of the mother developing pre-eclampsia.
The UtAD scan is a screening test that measures the blood flow through the uterine arteries. Uterine arteries are blood vessels that carry blood to your womb (uterus). The Doppler measurement uses sound waves to check if the blood is flowing through the arteries easily. These measurements are performed between 20-24 weeks of pregnancy, usually at the same time as your fetal anatomy scan. However, due to technical reasons e.g. raised BMI or your baby’s position the screening is not always possible.
Pre-eclampsia is a condition that usually develops after the 20th week of pregnancy and can lead to complications such as high blood pressure, blood clotting problems (HELLP syndrome) and convulsions. Although the exact cause of pre-eclampsia is unknown it is thought to occur when there is a problem with the placenta.
You will be offered UtAD screening if:
- You have certain medical conditions
- Your previous baby was small (<3rd centile)
- You had blood pressure problems in your previous pregnancy or you have had a stillbirth and your baby was small (<10th centile)
And / or
During this pregnancy you have:
- Low PAPPA <0.415 MoM, raised Inhibin A > 2.0 MoM or raised AFP > 2.2 MoM – these are hormones measured in your blood sample if you have screening for Down’s, Edward’s or Patau’s syndromes during your pregnancy.
- At your 18-20 week scan either:
- Your baby’s bowel is seen to be very bright (echogenic bowel)
- Your baby is considered smaller than expected (<10th centile)
- Your baby’s bowel is seen to be very bright (echogenic bowel)
- You have had significant heavy bleeding up to 24 weeks of pregnancy
- You develop gestational hypertension or pre-eclampsia between 20-24 weeks.
Risks
Although there are no known risks to you having the screening test, having the UtAD test may result in you having a positive screen which may cause you a lot of worry and anxieties. Please speak to your midwife or obstetrician who will be happy to answer your questions.
Benefits
The main benefit of the UtAD screening test is that early identification of a problem means the Maternity team can offer you extra appointments, scans and additional monitoring to closely observe you and your baby.
What happens if I have a normal UtAD screen?
If your UtAD screen is considered to be normal you will see an Obstetrician who will discuss with you your individualised plan of care which will include arranging any further growth scans that are required from 32 weeks of pregnancy.
If your UtAD screen is considered normal but you have Low PAPPA <0.415 MoM, Raised Inhibin A or Raised AFP your growth scans will commence from 35 weeks of pregnancy.
What happens if I have an abnormal UtAD screen?
If your UtAD screen is considered abnormal this may mean that:
- The Uterine Artery Pulsitility Index (a measure of blood flow through the artery in your placenta referred to as PI) is above the 95th centile
- There is a notch in the uterine artery Doppler trace
You will have your individualised care planned by your Obstetrician. This will include having the UtAD repeated at approximately 23+6 weeks of pregnancy. Often, this repeat UtAD is normal, in which case the plan of care reverts to that described in the normal screen. If it remains abnormal regular growth scans will be arranged from 28 weeks.
- Your baby’s estimated fetal weight (EFW) is plotting less than the 10th centile
If your baby’s weight is less than the 10th centile at the 1st UtAD screen, even if the Doppler is normal, you will be referred for a scan with a Consultant
Further support
Please speak to your Midwife or Obstetrician who will be able to answer any of your questions.