Donna has had higher blood glucose in the mornings than the evening before and wonders why when she has had nothing additional to eat. Keep it simple?

On insulin or not... If on insulin, from 3 to 8AM, one starts to increase the amounts of regulatory hormones (growth hormone, cortisol, and catecholamines) that work against insulin's action to drop blood sugars. These hormones, at a time when bedtime insulin is wearing out, result in an increase to AM blood sugars. If not insulin, people may have too low blood sugars overnight. The body's compensatory actions lead.
Glucose levels. Is she on insulin or oral diabetic medication? If so the medication may wear off in the evening. Sometimes the body secretes adrenalin if the sugar goes too low overnight and this causes a rise in the blood sugar in the early morning hours. A diabetologist or endocrinologist would be best to evaluate her.