Iowa Code § 681.9

The claims of all creditors, clearly and distinctly stated and sworn to by the claimant, or by some person acquainted with the facts, shall be filed in the office of the clerk of the district court within three months from the date of the first publication provided for in section 681.8, unless the court extends such time for all or some of such claimants, which it may do in its discretion where peculiar circumstances seem to justify such extension, but in no case shall such time be extended beyond nine months.