Iowa Code § 596.7: Revocation.

After marriage, a premarital agreement may be revoked only as follows:

1. By a written agreement signed by both spouses. The revocation is enforceable without consideration.

2. To revoke a premarital agreement without the consent of the other spouse, the person seeking revocation must prove one or more of the following:

a. The person did not execute the agreement voluntarily.

b. The agreement was unconscionable when it was executed.

c. Before the execution of the agreement the person was not provided a fair and reasonable disclosure of the property or financial obligations of the other spouse; and the person did not have, or reasonably could not have had, an adequate knowledge of the property or financial obligations of the other spouse.