Short answer: It depends on the leave. Under FMLA (employers with 50+ employees), coverage must continue on the same terms. For non-FMLA leave, it’s governed by the employer’s written policy and the carrier’s eligibility rules.
For leave that qualifies under the FMLA, the employer must maintain the employee’s group health coverage on the same terms as active work. For leave that isn’t FMLA-covered (for example at a smaller employer, or beyond the 12-week entitlement), whether coverage continues depends on the employer’s documented leave policy and the carrier’s active-employee eligibility rules. Setting a clear, consistent written policy avoids disputes and carrier eligibility problems.