Known allergy or adverse reaction to metformin

Multiple gestation

Abnormal obstetrical ultrasound suspicious for major congenital abnormality, known or suspected fetal aneuploidy

Medical comorbidities that increase risk for metformin use: renal insufficiency (creatinine \> 1.1 mg/dL), proteinuria (P:C \>0.3 or 24-hour urine protein \> 300 mg), active liver disease (acute hepatitis, chronic active hepatitis, persistently abnormal liver enzymes 3x above normal), inflammatory bowel disease (Crohn's and Ulcerative colitis), major hematologic disorder (including alloimmune and isoimmune thrombocytopenia).

Metformin for Preeclampsia Prevention in Pregnant Women With Type 1 Diabetes Mellitus

What this study is about