Giving birth is called labour for a reason.
Being active and up and about for most of it gives you that sense of independence and the ability to choose what ever position feels right for you. Strong tummy muscles make a great difference when it comes to pushing baby out. Keeping strong and Supple for the most important nine months of your life is crucial.
Physical fitness adds a quality to life that is especially relevant in pregnancy. Early in the nine months you may feel intensely fatigued, then as baby grows common aches and pains may present and then there is the weight of a full term baby to carry. Regardless of what is your level of fitness, within reason, you can improve it in pregnancy to be able to have that joyous nine months that waiting for baby can be.