38 wks pregnant.have diet controlled gd.never had issues with numbers(neither fasting).recently get even lower numbers.sign of aging placenta?

Confirm with doctor: I have seen your other questions and you had previously mentioned your numbers were 70-90s which is actually normal and not low. I would contact your Obgyn and have them go through all of them in detail. Likely you are just doing a good job controlling your gestational diabetes. Placental insufficiency is not very common in diet controlled GDM. A sonogram can be done to confirm