Iowa Code Title XVI. Criminal Law and Procedure [Chs. 687-916] § 720.2. Perjury, contradictory statements, and retraction

A person who, while under oath or affirmation in any proceeding or other matter in which statements under oath or affirmation are required or authorized by law, knowingly makes a false statement of material facts or who falsely denies knowledge of material facts, commits a class “D” felony. Where, while under oath or affirmation, in the same proceeding or different proceedings where oath or affirmation is required, a person has made contradictory statements, the indictment will be sufficient if it states that one or the other of the contradictory statements was false, to the knowledge of such person, and it shall be sufficient proof of perjury that one of the statements must be false, and that the person making the statements knew that one of them was false when the person made the statement, provided that both statements have been made within the period prescribed by the applicable statute of limitations. No person shall be guilty of perjury if the person retracts the false statement in the course of the proceedings where it was made before the false statement has substantially affected the proceeding.