A leisure centre could refuse to allow a pregnant woman to use certain gym equipment (for example, a rowing machine) after a certain point in her pregnancy if it reasonably believed that allowing her to use the equipment would create a risk to her health and safety and it would also refuse, for example, to allow a man with a serious heart condition to use the equipment.
An airline could refuse to allow a pregnant woman to travel beyond her 35th week of pregnancy if it reasonably believed that allowing her to travel would create a risk to her health and safety and it would also refuse people with other physical conditions that affect their health and safety to travel.