P. Bapat,1 K. Suffecool,2 B. Rosenn,3 U. Kiernan,4 E. E. Niederkofler,4 D. Daneman,1 G. Koren1; 1Hospital for Sick Children, Toronto, ON, Canada, 2St. Luke’s–Roosevelt Hospital Center, New York, NY, 3Icahn School of Medicine at Mount Sinai, New York, NY, 4Thermo Fisher Scientific, Tempe, AZ

BACKGROUND: Insulin detemir (Levemir®) is a long-acting basal insulin analog with greater stability and duration of action than regular human insulin. To date, the safety and efficacy of insulin detemir has been studied in one open-label randomized controlled trial in 310 pregnant women with Type I diabetes. Treatment with insulin detemir resulted in a lower fasting plasma glucose and noninferior glycemic control in late pregnancy compared with neutral protamine Hagedorn. Although this study demonstrated that rates of hypoglycemia were comparable between the groups, placental pharmacokinetics of insulin detemir were not studied. Therefore, the objective of this study was to determine whether insulin detemir crosses the term human placenta.
METHODS: Pregnant women with either gestational diabetes (GDM) or Type II diabetes who received insulin detemir were enrolled in this prospective observational study. Maternal and umbilical cord blood samples were collected immediately following delivery and frozen until analysis. Blood levels of insulin detemir were measured using the Thermo ScientificTM Mass Spectrometric Immunoassay Insulin Workflow, and the limits of detection for insulin detemir and endogenous insulin were 50 and 2 pM, respectively.
RESULTS: A total of 16 pregnant woman-neonate pairs who were treated with insulin detemir in the third trimester were included in this study. Daily doses of insulin detemir ranged from 10-96 units, and maternal plasma levels ranged between 159-3804 pM. Insulin detemir concentrations were below the level of detection (< 50 pM) in all umbilical cord blood samples.
CONCLUSION: Insulin detemir does not appear to cross the term human placenta in vivo, supporting previous studies that have suggested its fetal and neonatal safety.