Iowa R. Civ. P. 1.934
The jury in any case in which it renders a general verdict may be required by the court, and must be so required on the request of any party to the action, to find specially upon any particular questions of fact, to be stated to it in writing, which questions of fact shall be submitted to the attorneys of the adverse party before argument to the jury is commenced. The instructions shall be such as will enable the jury to answer the interrogatories and return the verdict. If both are harmonious, the court shall order the appropriate judgment. If the answers are consistent with each other, but any is inconsistent with the general verdict, the court may order judgment appropriate to the answers notwithstanding the verdict, or a new trial, or send the jury back for further deliberation. If the answers are inconsistent with each other, and any is inconsistent with the verdict, the court shall not order judgment, but either send the jury back or order a new trial.
Iowa. R. Civ. P. 1.934