Need for less tight glucose control in early pregnancy after embryogenesis due to high risk of maternal hypoglycaemia in women with pre-existing diabetes can be compensated by good control in late pregnancy.

Less tight glycaemic control, for example due to high frequency of severe hypoglycaemia in the first trimester, does not lead to increased adverse neonatal events if followed by tight control in the third trimester. Besides glycaemic control, excess weight gain is a modifiable predictor of adverse outcome.