This document contains interim rules governing the Newborns' and Mothers' Health Protection Act of 1996 (NMHPA). The interim rules provide guidance to employers, group health plans, health insurance issuers, and participants and beneficiaries relating to new requirements for hospital lengths of stay in connection with childbirth. The rules contained in this document implement changes to the Employee Retirement Income Security Act of 1974 (ERISA) and the Public Health Service Act (PHS Act) made by NMHPA, and changes to the Internal Revenue Code of 1986 (Code) enacted as part of the Taxpayer Relief Act of 1997 (TRA '97). Interested persons are invited to submit comments on the interim rules for consideration by the Department of the Treasury, the Department of Labor, and the Department of Health and Human Services (Departments) in developing final rules.