29 CFR §2590.715-2704

1. (a)No preexisting condition exclusions. A group health plan, or a health insurance issuer offering group health insurance coverage, may not impose any preexisting condition exclusion (as defined in § 2590.701-2).
2. (b)Examples. The rules of paragraph (a) of this section are illustrated by the following examples (for additional examples illustrating the definition of a preexisting condition exclusion, see § 2590.701-3(a)(2)):
3. (c)Applicability date. The provisions of this section are applicable to group health plans and health insurance issuers for plan years beginning on or after January 1, 2017. Until the applicability date for this regulation, plans and issuers are required to continue to comply with the corresponding sections of 29 CFR part 2590, contained in the 29 CFR, parts 1927 to end, edition revised as of July 1, 2015.