Sugar levels decreasing

Lily
Hi there, 
I'm 37 weeks and have been controlling my GDM through diet and exercise. I didn't fit the profile/ have any risk factors for developing GDM and am currently 55kilos and have always had a relatively healthy diet. Baby was slightly smaller than normal on his growth scan today which my obstetrician was happy about. I've recently noticed over the last few days that my sugar levels have been in the lower range I.e. Fasting levels around 3.8-4.5 and after eating things like creamy pasta (which in the past would've had a reading like 7-9) is now around 4-5 mark. Has anyone else heard of levels decreasing closer to due date?