The HEALTH : April 2018 | Page 17

columnist/ob-gyn APRIL, 2018 | The HEALTH 17 123RF The value of ultrasound in pregnancy What is ultrasound? Is it safe to use in pregnancy? Ultrasound is a high frequency sound which is beyond the hearing range of humans. It uses frequen- cies in a pulsed fashion from the probe, which is applied on to the abdomen or into the vagina to produce the image. The frequency of the sound wave varies with the probe used – transvaginal ultrasound has a higher frequency than the trans- abdominal one. For optimum imaging, a gel has to be applied to the scanned area. The image is then visualised on a screen in black and white with varying shades of grey. 3D imag- ing utilises 2D imaging in three planes, and there is an artificially coloured image which is a recon- structed image of the volume of