29 C.F.R. § 825.100

(a) The Family and Medical Leave Act of 1993, as amended, (FMLA or Act) allows eligible employees of a covered employer to take job-protected, unpaid leave, or to substitute appropriate paid leave if the employee has earned or accrued it, for up to a total of 12 workweeks in any 12 months (see § 825.200(b)) because of the birth of a child and to care for the newborn child, because of the placement of a child with the employee for adoption or foster care, because the employee is needed to care for a family member (child, spouse, or parent) with a serious health condition, because the employee's own serious health condition makes the employee unable to perform the functions of his or her job, or because of any qualifying exigency arising out of the fact that the employee's spouse, son, daughter, or parent is a military member on active duty or call to covered active duty status (or has been notified of an impending call or order to covered active duty). In addition, eligible employees of a covered employer may take job-protected, unpaid leave, or substitute appropriate paid leave if the employee has earned or accrued it, for up to a total of 26 workweeks in a single 12-month period to care for a covered servicemember with a serious injury or illness. In certain cases, FMLA leave may be taken on an intermittent basis rather than all at once, or the employee may work a part-time schedule.

(b) An employee on FMLA leave is also entitled to have health benefits maintained while on leave as if the employee had continued to work instead of taking the leave. If an employee was paying all or part of the premium payments prior to leave, the employee would continue to pay his or her share during the leave period. The employer may recover its share only if the employee does not return to work for a reason other than the serious health condition of the employee or the employee's covered family member, the serious injury or illness of a covered servicemember, or another reason beyond the employee's control.

(c) An employee generally has a right to return to the same position or an equivalent position with equivalent pay, benefits, and working conditions at the conclusion of the leave. The taking of FMLA leave cannot result in the loss of any benefit that accrued prior to the start of the leave.

(d) The employer generally has a right to advance notice from the employee. In addition, the employer may require an employee to submit certification to substantiate that the leave is due to the serious health condition of the employee or the employee's covered family member, due to the serious injury or illness of a covered servicemember, or because of a qualifying exigency. Failure to comply with these requirements may result in a delay in the start of FMLA leave. Pursuant to a uniformly applied policy, the employer may also require that an employee present a certification of fitness to return to work when the absence was caused by the employee's serious health condition (see §§ 825.312 and 825.313). The employer may delay restoring the employee to employment without such certificate relating to the health condition which caused the employee's absence.