Which finding would be most concerning for a client in her 26th week of pregnancy?

In the context of pregnancy, particularly around the 26th week, facial edema can be a significant concern. While some swelling is common due to the body's fluid changes and increased blood volume, pronounced facial edema may indicate potential issues such as gestational hypertension or preeclampsia. These conditions can be serious and might require immediate medical evaluation and intervention.

Back pain, light cramping, and normal fetal movement are generally considered typical experiences during pregnancy. While back pain and mild cramping can occur due to the physical changes the body is undergoing, they are often not alarming unless accompanied by other concerning symptoms. Normal fetal movement is a reassuring sign that the fetus is active and healthy at this stage in pregnancy.

Thus, facial edema stands out as the most alarming finding that could indicate a more serious underlying condition that warrants closer monitoring and possibly urgent care.