The use of insulin analogues in pregnancy

Excellent glycaemic control is essential in pregnancy to optimise maternal and foetal outcomes. The aim of this review is to assess the efficacy and safety of insulin analogues in pregnancy. Insulin lispro and insulin aspart are safe in pregnancy and may improve post-prandial glycaemic control in women with type 1 diabetes. However, a lack of data indicating improved foetal outcomes would suggest that there is no imperative to switch to a short-acting analogue where the woman's diabetes is well controlled with human insulin. There are no reports of the use of insulin glulisine in pregnancy and so its use cannot be recommended. Most studies of insulin glargine in pregnancy are small, retrospective and include women with pre-existing diabetes and gestational diabetes. There appear to be no major safety concerns and so it seems reasonable to continue insulin glargine if required to achieve excellent glycaemic control. A head-to-head comparison between insulin detemir and NPH insulin in women with type 1 diabetes showed that while foetal outcomes did not differ, fasting plasma glucose improved with insulin detemir without an increased incidence of hypoglycaemia. The greater evidence base supports the use of insulin detemir as the first line long-acting analogue in pregnancy but the lack of definitive foetal benefits means that there is no strong need to switch a woman who is well controlled on NPH insulin. There seems little justification in using long acting insulin analogues in women with gestational diabetes or type 2 diabetes where the risk of hypoglycaemia is low.