This is actually a common misconception — Kegel exercises are usually recommended for the postpartum period only. The primary reason for doing them is to improve or maintain pelvic muscle strength, but birth relies on the relaxation of pelvic muscles, not the tightening.
As for exercises that will actually make giving birth easier, it’s a rare woman who says giving birth is easy! It’s hard, demanding work. But staying active during your pregnancy can help. The best exercises are prenatal yoga, walking, and swimming. Make sure you talk with your provider before you start any new exercise program. It is also important to eat nutritious, whole foods and to stay well hydrated. Birth is physically demanding and the healthier you are going into it the better.