When should a pregnant woman seek immediate medical attention based on her symptoms?

A pregnant woman should seek immediate medical attention when experiencing sudden changes in vision and severe headaches because these symptoms can be indicative of serious conditions such as preeclampsia. Preeclampsia is characterized by high blood pressure and can lead to severe complications for both the mother and the fetus if not treated promptly. Sudden vision changes, including blurriness or disturbances, along with severe headaches, can signal complications that require immediate evaluation to ensure the safety of both the mother and the developing baby.

In contrast, back pain, mild cramps, and nausea with increased appetite, while they may be uncomfortable, are often common and less concerning symptoms during pregnancy. While they should be monitored and discussed with a healthcare provider if persistent or severe, they do not typically warrant the urgent medical attention that changes in vision and severe headaches do.