3rd Trimester GDM

Anyone find it harder to monitor glucose level during 3rd trimester? My 2nd trimester result was fantastic without insulin, just strict food intake & daily pregnancy cardio exercises. But when I'm at 3rd trimester, even with the same food, there could be a spike at times. Which I have no idea why. My result before meal upon waking up range from 5-5.5mmol (my Ogtt was 8.9mmol initially!), then when I had food intake, even with home cooked plain soupy food with wholegrain noodles / vermicelli (no issue for 2nd tri), it shoots up like mad for the 2 hours, but during 3rd hour, it went down from probably an 8mmol to 6.3mmol kind ? This is getting so frustrating!!