Professor Sabaratnam Arulkumaran:

They are medical terms, but what the medical people should understand or will understand is that what appears to be low risk can become high risk within minutes or hours in the antenatal, intrapartum or postnatal period. For example, we can say she is at low risk of thromboembolism but she can suddenly become medium or high risk. When it comes to termination, it has to be judged based on what is perceived by the clinician at that time. If it is a question of low risk and no termination, by the time one waits for it, it can become medium or high risk very suddenly.