If a pregnant women is not able to control her diabetes, will it hurt the baby?

Yup. You must work diligently to control your diabetes! Out of control diabetes causes the baby's body to create too much insulin, which also acts as a growth hormone. The baby can grow too large in the womb. This causes many potential complications with birth. Then after the baby's birth, low blood sugar becomes a problem, due to the baby secreting too much insulin. Do your best for your baby!
Yes. Uncontrolled diabetes is associated with many poor outcomes for the fetus.