Indiana Code Title 29. Probate § 29-1-3-6

Sec. 6. (a) The right of election of a surviving spouse given under section 1 of this chapter may be waived before or after marriage by a written contract, agreement signed by the party waiving the right of election, after full disclosure of the nature and extent of such right, if the thing or the promise given such party is a fair consideration under all the circumstances.

(b) The promise of marriage, in the absence of fraud, is sufficient consideration in the case of an agreement made before marriage.  An agreement waiving a right of election may be filed in the same manner as provided for the filing of an election under section 3 of this chapter.