How many ultrasound scans should a woman have during pregnancy?

Professor Teo, mothers before they deliver have ultrasound scans to establish how the foetus is doing. How many would you say are appropriate in terms of numbers? Well, the minimum number one should have is between two to three. Two is in the first trimester where you look at the viability of the foetus to get rid of any risk factors for chromosome abnormalities. There's one at 20 weeks where you look at all the foetal anatomy to make sure that you've got the hands and toes, but more specifically brain and structural abnormalities of the lungs and heart, basically any anatomical abnormalities. The third one is perhaps a well-being scan to ensure the baby is maintaining its growth velocity. Now obviously when people come see me on the private side, I have a scanner because I enjoy scanning and there are no risks to the baby for scanning then every time you come see me I use my ultrasound to look at the baby looking at the health of the baby more importantly. Thank you