As per me treat your female as normal till about 5 to 6 weeks and starts to show signs of being pregnant. perhaps give her little calcium and vitamins. later on you will need to feed her smaller but 2 or 3 meals. No forced exercise just let her walk the way she wants to, but do not let her put on weight.
Her food has to be nourishing. Royal canin is good and Eukanoba is also quite good and cheaper.