Moms who exercise regularly throughout pregnancy are more likely than non-active moms to have a normal birth without the need for medical intervention.
Women with low activity levels had a higher rate of cesarean section. In addition, it didn't matter of mom was overweight or obese - if she was active, she too would be less likely to need medical intervention during delivery.
Most exercise is appropriate for expecting mothers, but moms should not start an intense routine they're not used to. Just walking daily is enough to reap the benefits.