FMLA

Family and Medical Leave Act (29 U.S.C. §2601)

Employers with 50 or more employees must provide 12 weeks of unpaid leave during any 12 month period for the birth or placement of a child, or because of the serious health condition of the employee, the employee's spouse, child or parent.

It is the responsibility of the employer to designate leave as FMLA leave as soon as the employer has information that the leave is for a FMLA reason.
When the leave concerns a serious medical condition, the employer may require certification from a health care provider.
Except for health care benefits, all seniority and benefits are frozen until the employee returns from leave. The employer must maintain health care coverage for the duration of the leave on the same basis that it was provided before the leave began.
Persons on leave due to serious medical conditions may have intermittent and reduced schedule leave when medically necessary.