Obstetric dating ultrasound
When a sound wave strikes an object, it bounces back, or echoes.
By measuring these echo waves, it is possible to determine how far away the object is as well as the object's size, shape and consistency (whether the object is solid or filled with fluid).
We also have information on how your baby is monitored in labour.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions.
Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines.
They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
High-frequency sound waves are transmitted from the probe through the gel into the body.
The radiologist or sonographer may elect to examine an early pregnancy by means of transvaginal ultrasound in order to see the pregnancy more closely or to assess the cervix.Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a transducer that is used to do the scanning.The transducer is a small hand-held device that resembles a microphone, attached to the scanner by a cord.Ultrasound examinations do not use ionizing radiation (as used in x-rays), thus there is no radiation exposure to the patient.Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.