When shall an employee provide medical certification to support FMLA leave?

(See 29 CFR § 825.305) (a) An employer may require that an employee's leave to care for the employee's seriously-ill spouse, son, or daughter, as defined in section 31-51qq-1 of the Regulations of Connecticut State Agencies, or parent, or due to the employee's own serious health condition, be supported by a certification issued by the health care provider of the employee or the employee's ill family member. An employer shall give notice of a requirement for medical certification each time a certification is required; such notice shall be written notice whenever required by section 31-51qq-26 of the Regulations of Connecticut State Agencies. An employer's oral request to an employee to furnish any subsequent medical certification is sufficient. (b) When the leave is foreseeable and at least 30 days notice has been provided, the employee shall provide the medical certification before the leave begins. When this is not possible, the employee shall provide the requested certification to the employer within the time frame requested by the employer (which shall allow at least 15 calendar days after the employer's request), unless it is not practicable under the particular circumstances to do so despite the employee's diligent, good faith efforts. (c) In most cases, the employer shall request that an employee furnish certification from a health care provider at the time the employee gives notice of the need for leave or within two business days thereafter, or, in the case of unforeseen leave, within two business days after the leave commences. The employer may request certification at some later date if the employer later has reason to question the appropriateness of the leave or its duration. (d) At the time the employer requests certification, the employer shall also advise an employee of the anticipated consequences of an employee's failure to provide adequate certification. The employer shall advise an employee whenever the employer finds a certification incomplete, and provide the employee a reasonable opportunity to cure any such deficiency. (e) If the employer's sick or medical leave plan imposes medical certification requirements that are less stringent than the certification requirements of this section and section 31-51qq-31 of the Regulations of Connecticut State Agencies, and the employee or employer elects to substitute paid sick, vacation, personal or family leave for unpaid FMLA leave where authorized, only the employer's less stringent sick leave certification requirements may be imposed.