Management of pre-gestational diabetes in pregnancy

Pre-gestational diabetes – type 1 and type 2 diabetes mellitus – affects 1.7% of all pregnancies in the UK, and 1.3% of all pregnancies worldwide. In the UK there are now more pregnancies in women with type 2 than type 1 diabetes mellitus. Pre-gestational diabetes is associated with increased maternal and fetal risk including congenital abnormalities, stillbirth and pre-eclampsia; diabetic ketoacidosis also affects >1% of pregnancies. There are three targets for pre-pregnancy to reduce complications: glycated haemoglobin <48 mmol/mol (6.5%); folic acid 5 mg for at least 1 month before pregnancy; and avoidance of all teratogenic drugs. In pregnancy, tight glycaemic control is recommended, with a target blood glucose range of 3.5–7.8 mmol/litre. Increased doses of insulin are required through the course of pregnancy because of increasing insulin resistance. Childbirth is generally recommended in all those with pre-gestational diabetes between 37 and 38⁺⁶ weeks because of the risk of stillbirth and other complications. Continuous glucose monitoring and hybrid closed-loop insulin delivery systems have been shown to improve pregnancy outcomes in type 1 diabetes.