Mo. Rev. Stat. § 474.180
Current with changes from the 2023 Legislative Session
The election by a surviving spouse to take the share herein provided may be made at any time within ten days after the expiration of the time limited for contesting the will of decedent, except that if, at the expiration of the period for making the election, litigation is pending to test the validity or to determine the effect or construction of the will, or to determine the existence of issue surviving the decedent, or to determine any other matter of law or fact which would affect the amount of the share to be received by the surviving spouse, the right of the surviving spouse to make an election shall not be barred until the expiration of ninety days after the final determination of the litigation.
§ 474.180, RSMo