Systematic Literature Review of Basal Bolus Insulin Analogue Therapy during Pregnancy

Abstract

Currently standard insulin therapy for pregnancies complicated by diabetes mellitus (DM) is a combination of intermediate Neutral Protamine Hagedorn (NPH) and regular human insulin. In contrast, for non-pregnant individuals with diabetes, standard insulin therapy is basal bolus therapy (BBT) using a combination of rapid- and long-acting insulin analogues designed to mimic physiologic biphasic insulin secretion by the pancreatic beta cells. Although there are published reports describing use of BBT during pregnancy, due to the lack of strong clinical evidence regarding safety and efficacy of BBT during pregnancy, its use has not been adopted as standard insulin administration during pregnancies complicated by diabetes mellitus. To evaluate the evidence for this discrepant clinical management, we conducted a systematic review. Search strategy and selection criteria: PubMed, Medline, Cochrane Database of Systematic Reviews for publications between 1996 and 2014. Search terms: lispro, apart, glargine, detemir, glulisine, Humalog, NovoLog, Lantus, Levemir, Apidra, pregnancy, and diabetes. Included: randomized clinical trials, prospective and retrospective cohort analyses, case-control studies and case series and reports. Search limited to human studies and English language. Excluded: review articles. Nineteen studies were identified that assessed safety/efficacy of rapid-acting insulin analogues, lispro and aspart, and 23 studies that assessed the long-acting insulin analogues, glargine and detemir, in pregnant patients complicated with pregestational (PGDM) and gestational diabetes mellitus (GDM). The principal efficacy endpoint examined in the selected studies was glycated hemoglobin levels. Other study outcome variables to assess maternal glycemic control included fasting and postprandial glucose levels, large for gestational age (LGA) infants, mean birth weight, congenital malformations, and incidence of hypoglycemic events. Compared to conventional insulin therapy, insulin analogue use provided similar overall glycemic control in pregnancy. In addition, they contributed to greater postprandial glucose control. There was no compelling evidence that insulin analogue use was associated with any significant differences in maternal and neonatal outcomes, particularly in terms of incidences in maternal and neonatal hypoglycemia, LGA, and congenital malformations. Given the documented benefits of physiological insulin replacement, we found no reason that BBT should not be standard prenatal care for pregnancies complicated by DM.