Uterine Artery Doppler Scan
All pregnant women will be offered a dating scan at around 12 weeks and a fetal anomaly scan (FAS) around 20 weeks of pregnancy.
Some women may have risk factors that could limit a baby’s ability to develop to its full potential or cause it to be born small.
We can offer a Uterine Artery Doppler scan to assess this risk and plan ongoing care for your pregnancy.
What is the Uterine artery Doppler ultrasound screen?
Uterine arteries are the vessels that carry blood to your womb (uterus). Every woman has two uterine arteries, one on each side of the womb. These arteries supply the blood flow to the womb, which then feeds the placenta. If there is good blood flow in these arteries, the placenta develops normally, helping the baby grow in a healthy way inside the womb.
The uterine arteries can be examined by ultrasound through the abdomen, usually at the same time as the fetal anomaly scan between 20 and 24 weeks pregnancy. This examination takes around 5 minutes and does not cause any pain/harm to either you or your baby.
What will happen if I have a normal uterine artery Doppler ultrasound screen?
If the uterine artery Doppler ultrasound screen is considered normal, this means that the blood is flowing easily from you to the womb (low resistance pattern). It is unlikely to have problems with early fetal growth restriction. Your
obstetrician will offer growth scans to monitor your baby’s growth starting from 32 weeks.
Even if the Doppler results are normal, you will be referred to a consultant in the Fetal Medicine Unit for close monitoring of your baby if the baby is small at the uterine artery Doppler ultrasound screening.
What will happen if I have an abnormal uterine artery Doppler ultrasound screen?
If the uterine artery Doppler ultrasound screen is considered abnormal, this means that the blood is having to work harder to flow to the womb (high resistance pattern). This suggests that there is an increased chance of having a small baby or developing pre-eclampsia (high blood pressure) in this pregnancy.
Your consultant obstetrician will make a personalised plan for your pregnancy. This will include regular growth scans of your baby from 28 weeks gestation, and close monitoring of your blood pressure.
An abnormal result does not mean that your baby is unwell. It only means that we need to monitor the pregnancy closely so that we can identify any problems early.
Is there anything I can do?
There is no treatment to improve the blood flow pattern. Your midwife/obstetrician may have already discussed Aspirin to reduce the risk of placental problems/ fetal growth restriction. This should be continued as directed until 36 weeks.
If you smoke, it is important that you stop. Smoking can affect how the placenta works and the growth of the baby. Your midwife can make a referral to cessation services if you need support.
It is very important to be aware of your baby’s movements. Every pregnancy is different; however, if you have any concerns about your baby’s movements, you should contact Delivery Suite immediately, as this may be an important warning sign that they are unwell. Contact Delivery Suite Triage Unit (Ward 31) in Luton and Dunstable University Hospital on 01582 329574 for advice and assessment. For Bedford Hospital, you can contact maternity triage on 01234792060. It is a 24-hour service.
What happens if my baby is small?
If your baby is found to be smaller than expected then you will be referred to either our Growth Monitoring Clinic or Fetal Medicine. This may require more frequent scans, fetal heart monitoring in our Day Assessment Unit and possibly early delivery. Our midwives and obstetricians will support you and keep you updated throughout about any decisions.
Who can I speak with if I need further information?
The majority of pregnancies are uncomplicated and babies grow normally even if you are found to have risk factors for growth problems. If you are concerned or have any questions, you are welcome to speak with your community midwife or your consultant Obstetrician.