A nurse is collecting data from a client who is at 20 weeks of gestation and has been taking ferrous sulfate. For which of the following findings should the nurse monitor as a common adverse effect of iron supplementation and report to the provider?

Iron supplementation commonly causes constipation, which is due to the iron's effect of slowing down bowel movements and increasing water absorption in the intestines. Dry mouth is not a common adverse effect of iron supplementation. It is more commonly associated with medications that can cause xerostomia (dry mouth), such as certain antihistamines or anticholinergic drugs. Tinnitus, a perception of ringing or noise in the ears, is not typically associated with iron supplementation. Tinnitus can be caused by various factors, such as exposure to loud noises, ear infections, or certain medications, but it is not directly related to iron supplementation. Hematuria, the presence of blood in the urine, is not a common adverse effect of iron supplementation. It can be caused by various conditions affecting the urinary system, such as urinary tract infections, kidney stones, or bladder issues, but it is not directly related to iron supplementation.