Gestational diabetes test

Patient: My wife is 26 weeks pregnant with twins and just had a 3 hour glucose test. Her fasting number was 94, 195 at 1 hour, 137 at 2 hours and 302 at 3 hours. How is it possible for the 3 hour number to be more than double that of the 2 hour number especially after her level dropped?

Symptoms: None

Doctor: