Advice after your nerve block for surgery
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Your womb (uterus) receives blood through two blood vessels called uterine arteries, one on each side. These arteries supply blood to the placenta, which provides your baby with oxygen and nutrients.
When blood flows easily through these arteries, the placenta can work well and support your baby’s growth.
During your anatomy scan, doctors may use a Doppler ultrasound to check how blood is flowing through the uterine arteries. This scan uses sound waves to see whether:
- blood is flowing easily (low resistance), or
- blood is flowing with more difficulty (high resistance)
- Low resistance: This is reassuring, and no further tests are usually needed.
- High resistance: This means there is a higher chance of:
- your baby growing more slowly than expected, or
- you developing pre-eclampsia (a condition related to high blood pressure)
A high resistance result does not mean these problems will definitely occur. It simply means closer monitoring is needed. You will be offered extra scans and appointments so any concerns can be picked up early.
- If you smoke, stop smoking – smoking can harm the placenta and your baby’s growth. Ask your midwife for referral to stop smoking services.
- Pay attention to your baby’s movements – this is a good way to monitor your baby's wellbeing
- If your midwife told you to take aspirin, take it as advised.
No – this is not an illness, so no treatment is needed.
No – having high resistance in this pregnancy does not mean it will happen again.
Being told that extra tests are needed can feel worrying. However, most babies develop normally, so try not to feel alarmed.
If you have any questions or concerns:
- talk to your community midwife, or
- speak with your obstetrician (the doctor caring for you during pregnancy).
Contact us
If you have any queries relating to this information, please contact the Maternity service.
About this information
Service:
Maternity
Reference:
M/036
Approval date:
1 March 2026
Review date:
1 March 2029
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.