Women’s Health and Cancer Rights Act:

The Women's Health and Cancer Rights Act (WHCRA) includes protections for individuals who elect breast reconstruction in connection with a mastectomy.

WHCRA provides that group health plans and health insurance issuers that provide coverage for medical and surgical benefits with respect to mastectomies must also cover certain post-mastectomy benefits, including reconstructive surgery and the treatment of complications (such as lymphedema).

https://www.dol.gov/agencies/ebsa/laws-and-regulations/laws/whcra