What is Ultrasound?

What is Ultrasound?

High frequency sound waves with frequencies above 20KHz. It is useful as a diagnostic tool in pregnancy to provide detailed information about the health of your unborn child without exposing the mother to ionising radiation (xrays)


How it works

Ultrasound imaging uses the echoes formed when sound waves bounce back from body organs to build up a picture.


Is Ultrasound safe? Are there any risks?

At present there is very little scientific information available with which to access the exposure to ultrasound on the unborn child.

Antenatal scans have been performed for 40 years without apparent ill-effects.

Subtle effects have been reported in studies of brain development in small animals and some studies in humans indicate changes in neurological function following in-utero exposure.

While this data is not considered to provide clear evidnec of a specific hazard the possibility of subtle long term effects cannot be ruled out.


To minimise these risks we use the ALARA principle (as low as is reasonably achievable) to perform any scan therefore reducing the thermal and cavitation affects on the baby. There is little direct evidence on the safety of modern techniques but no ill affects have been reported.

Bay Ultrasound only employ fully qualified HCPC registered Sonographers to ensure you and you baby are safe from harm.

We will inform you of the risks and benefits to scan and will only be performed when necessary to reduce the risks to the baby particularly in the first trimester.


Health Protection Agency advises that people should continue using Ultrasound for diagnostic reasons. Such use has an established track record for safety and is regulated.

HPA advice states that there is no known reason to with-hold diagnostic imaging in pregnancy provided it complies with existing exposure guidelines and performed by a specialist health care professional who is trained in ultrasound safety and can ensure compliance with exposure guidelines and using well maintained equipment.

Such specialists can offer appropriate advise should any abnormality or adverse event be observed.


Future research 

Continues to be monitored in UK and abroad.

Because of th uncertainties surrounding the possible neurological effects from ultrasound exposure, the HPA supports the need for research, particularly with regard to in-utero exposure. The HPA will update advise in the future based on careful analysis of the latest evidence.


References –

Health Protection Agency

British Medical Ultrasound Society