Insulin aspart (rDNA origin) injection (brand name, NovoLog), a rapid-acting human insulin analog, provides better control of blood glucose following meals than regular insulin in women with gestational diabetes, according to new research published this month in Diabetes Care. The findings are important because better control of post-meal blood glucose (postprandial glycemia) in gestational diabetes is associated with improved maternal and neonatal outcomes and with healthier birth weight.

"Because insulin aspart acts more rapidly than regular human insulin, we hypothesized it would provide better postprandial glycemic control -- which is just what we found," said lead investigator David Pettitt, M.D. from the Sansum Medical Research Institute in Santa Barbara, California. "Given the link between postprandial glucose levels and pregnancy outcomes shown in other studies, these results suggest insulin aspart may improve outcomes for both mothers and infants," he said.

NovoLog is indicated for the control of hyperglycemia in adult patients with diabetes mellitus. Because it has a more rapid onset and shorter duration of action than regular human insulin, it is recommended to use NovoLog in combination with an intermediate or long-acting insulin, and to eat immediately after injection. NovoLog is contraindicated during episodes of hypoglycemia and in patients hypersensitive to NovoLog or one of its excipients. Hypoglycemia is the most common adverse effect of insulin therapy, including NovoLog.

Gestational diabetes mellitus (GDM), diabetes that is first recognized and diagnosed during pregnancy, occurs in about seven percent of pregnancies, though prevalence rates vary with ethnicity and maternal age. Pregnant women should be assessed for risk of GDM at their first prenatal visit, and retested between the 24th and 28th week of pregnancy.

GDM is associated with an increased risk for preeclampsia, Cesarean delivery, congenital abnormalities, perinatal mortality, maternal hypertension and diabetes, and obesity and diabetes in the offspring. The most common neonatal complication of GDM is abnormally large body size (macrosomia), which occurs in as many as 40 percent of cases. Neonatal macrosomia, in turn, is associated with increased risk of developing obesity in childhood and adulthood. GDM is treated through diet but may require insulin therapy to maintain adequate control of blood glucose levels. Oral hypoglycemic agents, used to treat type 2 diabetes, are generally not used to treat GDM because they can be toxic to the fetus.

The study included 15 women with GDM who had inadequate glycemic control by diet alone. On three consecutive days, participants consumed breakfast test meals, one with no insulin administered and the others after injection of either insulin aspart or regular human insulin (RHI). Researchers measured levels of plasma insulin, glucose and C-peptide concentrations for four hours after breakfast. C-peptide is a small protein released along with insulin by the pancreas.

Insulin aspart was more effective than RHI in blunting the postprandial glucose peak 60 minutes after the meal (112, 116 and 123 mg/dL for insulin aspart, RHI and no insulin, respectively; p<0.01 and p<0.05 for insulin aspart and RHI, respectively, vs. no insulin). The overall increase in the amount of glucose in the bloodstream following the meal was significantly lower with insulin aspart, but not with RHI, compared to no insulin (7.1, 30.2 and 29.4 mg hr/dL for the 3-hour area under the curve for insulin aspart, RHI and no insulin, respectively; p=0.018 and 0.997 for insulin aspart and RHI, respectively, vs. no insulin). The peak insulin concentration was higher and the peak C-peptide concentration was lower with both types of insulin compared to no insulin.

Dr. Pettitt noted that regular human insulin is the current standard therapy for gestational diabetes when diet therapy fails to adequately control blood glucose concentrations, and insulin analogs are not currently recommended. "But that may change," he said, "if additional studies verify our findings and ensure the safety of insulin aspart in women with gestational diabetes."

The study was supported in part by Novo Nordisk Pharmaceuticals, Inc.