We are asking you to take part in this research study because you are diagnosed with pregestational Type 2 Diabetes Mellitus or Gestational Diabetes Mellitus requiring insulin therapy in pregnancy. Currently, many hospitals differ among use of insulin for management of DM in pregnancy, with NPH, glargine and detemir being the most commonly used forms of basal insulin. Outside of pregnancy, NPH is rarely used with glargine and determir being the more common forms of insulin used due to their fewer episodes of hypoglycemia in these patients. Detemir has been well studied in pregnancy and found to be noninferior to NPH. Unfortunately, glargine has not been as well studied in pregnancy. Thus, with this study we want to compare glargine and NPH.

The purpose of this study is to compare two different forms of insulin (Glargine and NPH) that we regularly use to manage diabetes mellitus in pregnancy.

This is an open-label, noninferiority, prospective randomized study. Patients will be randomized to either be treated with NPH insulin for management of diabetes mellitus in pregnancy, or with Glargine insulin. We will include all pregnant patients managed by the Maternal Fetal Medicine team at Loyola University of Medical Center that have pregestational Type 2 Diabetes Mellitus or Gestational Diabetes Mellitus requiring insulin. Our primary outcome is hypoglycemia.

We provide patients with insulin teaching, a referral to diabetic nutrition education, and instructions for hypoglycemic events. Patients are instructed to continue monitoring blood glucose 4 times a day (fasting and 2 hours after each meal), log their blood glucose values in MyLoyola chart, continue routine prenatal care with maternal fetal medicine/high risk obstetric clinic, and continue routine ultrasound with serial growth ultrasounds and antenatal fetal surveillance. The study is voluntary, and the patients will receive the same care and number of visits regardless of whether they choose to participate in the study or not, regardless of which arm they are in within the RCT.

Inclusion Criteria:

• Patient requiring initiation of insulin therapy for Gestational Diabetes Mellitus or Type 2 Diabetes Mellitus in pregnancy
• At least 18 years old
• Insulin started prior to 34 weeks gestation
• Established prenatal care by 14 weeks gestation

Exclusion Criteria:

• Those under the age of 18 years old
• Those unable to consent in english
• Allergy to insulin
• Controlled with only diet modification or the use of oral antihyperglycemics
• Has diagnosis of Type 1 Diabetes Mellitus
• Receiving insulin through an insulin pump

It is not documented in the patient's electronic medical record if they are in the study and were randomized or if they declined randomization.