; and (B) if not used by the covered employee before the end of the 12-month period (as referred to in section 102(a)(1) of the Family and Medical Leave Act of 1993 ( 29 U.S.C. 2612(a)(1) )) to which it relates, shall not accumulate for any subsequent use. . (b) Effective date The amendment made by this section shall not be effective with respect to any birth or placement occurring before the end of the 6-month period beginning on the date of the enactment of this Act. 4. Conforming amendment to family and medical leave act for gao and library of congress employees (a) Amendment to family and medical leave act of 1993 Section 102(d) of the Family and Medical Leave Act of 1993 ( 29 U.S.C. 2612(d) ) is amended by adding at the end the following: (3) Special rule for gao and library of congress employees (A) Substitution of paid leave An employee of an employer described in section 101(4)(A)(iv) taking leave under subparagraph (A) or (B) of subsection (a)(1) may elect to substitute for any such leave any paid leave which is available to such employee for that purpose. (B) Amount of paid leave The paid leave that is available to an employee of an employer described in section 101(4)(A)(iv) for purposes of subparagraph (A) is— (i) the number of weeks of paid parental leave in connection with the birth or placement involved that correspond to the number of administrative workweeks of paid parental leave available to Federal employees under section 6382(d)(3)(A) of title 5, United States Code