Question about my parents' B2 visa. Thanks!!

When I filled in the visa application form for them in August, I applied for 6 months stay for them. They came this September and are helping us with our newborn-daughter. My mom keeps asking me if she can come back here to help us roughly after a month she goes back to China (in March).

I think she probably can and the officer will probably grant her another few months stay at the airport next time she comes. But I am wondering if there will be any effect next time she applies for visa in China.

Can she do that without having any trouble obtaining visa again?

Thanks to all!