My wife recently gave birth and is currently on Materinity Leave w/ her company in MA, she is thinking about not returning to work to become a fulltime mom. If she were to put in her 2-weeks notice when her maternity benfits end (ie go into unpaid leave status), will she have to reimburse her company for the official maternity leave time that she was already paid for?

No, but she may be required to reimburse the employer for any health insurance premiums they've paid on her behalf.

Does this include the premiums for the time when she was on paid maternity leave?

Yes, it does.

Note that I am saying this CAN happen, not that it will. The law gives employers the right to require the repayment of health insurance premiums in these circumstances; not all or even most employers avail themselves of that right.

Thanks for the quick answer.. So to elaborate on the other part of my question, the pay that my wife had accrued during her time on maternity leave does not get taken away from her, right?

No, I already said that.

Sorry to belabor this thread cbg, but I just need one more clarification about the premiums..
When you say that 'she may be required to reimburse the employer for any health insurance premiums they've paid on her behalf', does this mean that she has to pay for the percent that they normally cover in on her paycheck?
For example, if the employer paid 70% of the monthly cost for the health plan, she will have to reimburse them for this 70%?

Yes, that's what I mean. But again, keep in mind that this is what they MAY require. There is no guarantee that they WILL require it. In my experience most employers find it more trouble than it's worth.

I understand the necessity for fully understanding - don't worry about it. :)

Thank you very much! I'm glad I came across this site :)