There are numerous risks of uncontrolled diabetes during pregnancy, including: 1) Large baby - The baby may have excessive weight at the time of birth (called macrosomia). Such babies are more difficult to deliver, are more likely to sustain birth injuries, and may lead to the requirement of a C-section. 2) Early (preterm birth) or miscarriage. 3) Respiratory distress syndrome - Breathing difficulties after birth, usually related to preterm birth. 4) Low blood sugar after the baby is born - This can sometimes lead to seizures in the newborn. 5) The baby has a higher chance of developing obesity and T2DM later in life.