If your urine tested high for glucose you should have your screening early. Diabetes in pregnancy
is a risk for the baby.
Insulin resistance increases rapidly as the pregnancy progresses. While the A1c of 5.2 is quite reasonable, it measures the last 3 months and it could be that your sugars have recently increased.
In the meantime limit your carbs (particularly sweets, white bread, fruit and fruit juice, soda) and try to walk 30 minutes twice a day, if possible.