Could i use teeth whitening products at home while pregnant? such as toothpaste or a whitening pen ?

Avoid overuse: There's insufficient data either way. I think at some point in time sufficient research will have been done to decide this issue. In the meantime, while pregnant the less chemicals you assault your body with the better. Start with a good professional cleaning @ your Dentist's office. Brush 2 minutes 2x/day w regular toothpaste. Floss daily. Remember, over whitening can actually cause damage.