Final answer:
When a pregnant client with mild preeclampsia reports an upset stomach and epigastric pain, the home care nurse should notify the healthcare provider immediately.
Step-by-step explanation:
Mild preeclampsia is a condition that affects pregnant women and is characterized by high blood pressure and organ damage. One symptom of preeclampsia is epigastric pain, which can indicate liver involvement. Therefore, the nurse should notify the healthcare provider immediately to ensure proper medical attention and evaluation of the client's condition. This is important because preeclampsia can progress rapidly and pose risks to both the mother and the baby.