Safety of insulin use during pregnancy
The choice of insulin and mode of insulin delivery for women with diabetes who are pregnant or planning pregnancy should be reviewed on an individual basis. The Australian Therapeutic Goods Administration (TGA) pregnancy categorisations differ for individual insulins, but none of the currently available insulin preparations have been demonstrated to cross the placenta. TGA pregnancy categories are accessible through icons in Action profiles of insulin formulations. In addition, some insulins are not subsidised by the Pharmaceutical Benefits Scheme (PBS) for patients with type 2 diabetes1.
Some rapid-acting insulins (insulin aspart [NovoRapid], faster-acting insulin aspart [Fiasp] and insulin lispro [Humalog]) are safe to use and are preferred over short-acting insulins in pregnancy. Use of the rapid-acting insulin glulisine (Apidra) is not advised because safety data are lacking. Short-acting neutral insulins (Actrapid, Humulin R) have been used extensively in pregnancy, but they are usually only used in special situations.
Isophane insulin (Protaphane, Humulin NPH) has been used extensively in pregnancy.
Insulin detemir (Levemir) is safe in pregnancy.
Insulin glargine (Optisulin) has been used extensively in pregnancy. Its long duration of action may increase the likelihood of hypoglycaemia mid to late morning, and it can be difficult to titrate if additional daytime basal insulin is required.
Concentrated neutral insulin (Humulin R 500 units/mL) has not been formally studied in pregnancy but may be considered in women requiring very high doses of insulin (eg more than 100 units per dose).
At the time of writing, concentrated insulin glargine (Toujeo 300 units/mL) and insulin degludec/aspart (Ryzodeg 70/30) have not been studied in pregnancy.