If she is used to being bathed yes you can. A lot of people wash or bath believing it will remove the scent, it does not dogs are not fooled by any attempts to hide her true state. But you have not asked that and if she just needs a bath, no problem, but not if you have never done it before.
Also I wouldn't bath her if she is to be mated. It won't wash away all the scent, but it could be enough to confuse a stud dog, making her smell less desirable?.
You can bath your bitch anytime, If I plan to mate, I try to bath them before the heat. As Brainless said some stud dogs will not perform if you take away the smell, others will to comand. Depends on the stud dog.