Current guidelines in many countries including Australia, the United Kingdom and United States recommend preconception care of diabetic women. Pregnant women with type I or type II diabetes are at a greater risk of adverse outcomes in pregnancy such as high blood pressure (gestational hypertension) and preterm births. Pregnancy can also accelerate the development of diabetic complications (retinopathy, nephropathy, neuropathy, ischaemic heart disease, cerebrovascular disease, peripheral vascular disease). Babies born to mothers with type I or type II diabetes diagnosed before pregnancy may be larger and are at greater risk of infant death and congenital abnormality (such as neural tube defects including anencephaly and spina bifida). These infants are also at risk of developing type II diabetes in the long term. Because of the strong association between good control of a woman’s blood sugars (glycaemic control), as measured by haemoglobin A1c, and reduced congenital anomalies, glycaemic targets are central to preconception care.
This review evaluating preconception care management protocols for women with pre-existing diabetes identified only one trial (involving 53 women) that was eligible for inclusion. None of the prespecified outcomes of the review were reported by this trial. Haemoglobin A1c data were reported as mean changes from baseline and could not be included in this review. Therefore, it is unclear what effect preconception care for diabetic women has on maternal and infant health outcomes based on evidence from randomised controlled trials.