This past month I had two, one during the night at 54 mg/dL (3 mmol/L) and one before breakfast (fasting) at 68 mg/dL (3.8 mmol/L). Both were most-likely miscalculations on my part. I count carbs and bolus for the carbs, which is basically my version of the pump using multiple daily injections (MDI). The better calculations, on my part, return better blood glucose numbers. Fortunately, when hypo's occur at night I awake and now with experience I know that there is a reason for the awakening.
If you are interested in what I do here is the
link.