Why is preconception care important for women with pre-existing diabetes, and what are the specific risks to the baby if blood glucose levels are not well controlled before and during early pregnancy?

Preconception care is important because organ development and birth defects can occur very early in pregnancy, often before a woman knows she is pregnant. If blood glucose is not well controlled before and in early pregnancy, babies of women with diabetes are about five times more likely to be stillborn and twice as likely to have a major congenital anomaly, and there are also higher risks of miscarriage, preterm delivery, and macrosomia. Achieving an HbA1c of 48 mmol/mol or less before conception is recommended to reduce these risks.

Preconception care reduces adverse pregnancy outcomes by optimizing glucose control and addressing other health factors before conception. The source states that suboptimal glycaemic levels both before and in the early stages of pregnancy are associated with adverse pregnancy outcomes. Specific risks to the baby include a fivefold increased likelihood of stillbirth and a doubled risk of major congenital anomaly compared with the general maternity population. The source also notes significantly higher rates of miscarriage, pre-eclampsia, perinatal mortality, preterm delivery, and macrosomia in women with diabetes. Because congenital anomalies can occur very early in pregnancy, planning is essential. The recommended approach is to achieve an HbA1c of 48 mmol/mol or less before pregnancy, with early referral to specialist services, monthly HbA1c checks, folic acid 5 mg daily for at least three months before conception and until 12 weeks of pregnancy, medication review, and contraceptive advice when glucose is not yet optimal.