How much time before returning on visitor visa

[WhyThisDelay]

I'm planning to call my mother who has a 10 year multiple entry visa from Sept 2010 to January 2011. My question is whether I can call my mom again by end of May next year (planning on having a baby around that time)?
Will that create any issue at the port of entry about entry or length of her trip?

 

[Triple Citizen]

A genuine visitor to the US should never spend more than 6 months in the US during any rolling 12 month window. Use this as a yardstick.

Will that create any issue at the port of entry about entry or length of her trip?

 

[Concerned4us]

You having a baby is not a justification for an frequent, extended visits. If your mother wishes to come in May 2011, she should either cancel her planned trip or come for a very, very short stay. Returning quickly can result in a shorten authorized stay, a denial of entry, or revocation of visa if it appears that she intends to violate US laws while here. Note, regular babysitting is illegal work and not an approved activity for visitors.