Okla. Stat. tit. 70 § 6-104.1
After exhausting sick leave and extended leave pursuant to Sections 6-104 and 6-104.5 of this title and maternity leave pursuant to Section 1 of this act, a full-time teacher who, with the proper approval of the district board of education, takes not more than ninety (90) school days of leave without pay to care for the teacher's child during the first year of the child's life, shall receive full credit for the days on leave without pay as though the teacher had been on leave with pay for purposes of computing experience for the minimum teacher salary schedule. A teacher on leave without pay pursuant to this section who pays the actuarial cost, as determined by the Board of Trustees of the Teachers' Retirement System of Oklahoma, shall have the period during which such leave without pay is taken, counted toward retirement service credit as though the teacher had been on leave with pay. The teacher shall notify his or her employer and the System in writing within thirty (30) days from the date he or she returns to service that he or she will pay such actuarial cost. The teacher shall have up to twelve (12) months from the date he or she returns to service to pay such actuarial cost.
Okla. Stat. tit. 70, § 6-104.1