Effectiveness of Metformin Compared to Insulin in Pregnant Women With Mild Preexisting or Early Gestational Diabetes

Pilot Study of Metformin vs. Insulin in Pregnant Overt Diabetics (MIPOD)

Many women come into pregnancy with diabetes that is controlled with either Metformin or diet control; however, the current standard of care for the treatment of preexisting diabetes in pregnancy is insulin. Metformin is widely used in the non-pregnant population for glycemic control, and has been used in pregnancy for other indications without adverse maternal or fetal outcomes. What remains unproven is the ability of Metformin to adequately control glucose in women during pregnancy.

Our goal is to randomize 100 women who enter pregnancy with diabetes that is controlled by either diet or an oral agent and women who are found to have an abnormal glucose challenge test at less than 20 weeks to either standard treatment with weight based Regular and neutral protamine Hagedorn (NPH) insulin or Metformin. Our hypothesis is that Metformin will provide glycemic control that is equivalent to insulin in these women.

Inclusion Criteria:

• Receiving prenatal care at University of North Carolina (UNC), Chapel Hill Obstetric clinics and planning delivery at UNC Women's Hospital
• Diagnosis of Diabetes prior to pregnancy with use of an oral hypoglycemic agent or dietary control
• Diagnosis of early gestational diabetes prior to 20 weeks gestation via abnormal 3 hour glucose challenge testing using the national diabetes data group (NDDG)criteria
• Less than 24 weeks at study enrollment
• Singleton or twin pregnancy
• English or Spanish speaking
• Able to give informed consent

Exclusion Criteria:

• End organ complications of diabetes (retinopathy, renal insufficiency, etc.)
• Prior need for insulin for glycemic control
• History of diabetic ketoacidosis (DKA) or hyperosmolar state
• Prior adverse reaction (ie. lactic acidosis) or allergy to Metformin
• Kidney or liver disease
• Significant medical co-morbidities (lupus, cystic fibrosis, etc.) Hypertension controlled on one medication, well controlled asthma, and well controlled thyroid disease are not excluded.