discuss their health with a doctor first.
According to Louise Whyte, founder of Penelope Fitstar, women undergoing a low risk pregnancy can gain "enormous" benefits from exercising during pregnancy.
However, it is wise to discuss which exercises are suitable with a doctor before embarking on a new health regime.
Ms White said: "Expectant mums should listen to their bodies, not work to exhaustion, take regular rest breaks and see the nine months as a time to enjoy exercising rather than pushing themselves to achieve personal bests."
She added that exercise should help to make women "fitter and stronger" before they go in to labour.
They should also find it easier to regain their pre-pregnancy figure if they keep fit while carrying their baby.