Which symptom could indicate a serious complication in a pregnant patient with high blood pressure?

Flashing spots in vision are a significant symptom that could indicate a serious complication in a pregnant patient with high blood pressure, particularly preeclampsia. This condition can impact the central nervous system and may signal that the patient is experiencing visual disturbances, which can be associated with increased blood pressure and potential progression to more severe issues such as eclampsia, characterized by seizures.

While fatigue and nausea can be common in pregnancy and might relate to a variety of benign conditions, they are less specific indicators of severe complications associated with hypertension. Similarly, swelling of the feet is often a normal occurrence during pregnancy and does not necessarily correlate with immediate medical concerns unless it is accompanied by other alarming symptoms. Therefore, visual disturbances like flashing spots are critical warning signs that should prompt immediate evaluation and management to prevent severe outcomes.