Myo-inositol is important for glucose homeostasis and has been shown to improve insulin sensitivity. This is a prospective cohort pilot study to determine daily glycemic pharmacokinetics and metabolic influences of myo-inositol supplementation using continuous glucose monitoring system (CGMS) and pre- and post-supplement blood work in high risk pregnancies and women diagnosed with gestational diabetes mellitis (GDM). Risk factors include: obesity, previous pregnancy with GDM, family history of diabetes, glucose intolerance, and polycystic ovarian syndrome (PCOS). Women will have a CGMS device placed on day one and begin with 3 days of placebo plus folic acid (400mcg) to determine baseline glycemia and metabolic levels. For the final 4 days, women with take myo-inositol supplementation (4g) plus folic acid (400mcg). The CGMS device will be removed on day 7 when final blood work will be obtained. Self-capillary glucose testing 4 times per day is recorded to calibrate CGMS glucose values. These observations will help determine the effects of myo-inositol on overall mean glucose and other metabolic factors in high risk and GDM patients, identify pharmacokinetic discipline in pregnancy, and develop the groundwork for future prospective clinical trials for the prevention and/or augmentation in treatment GDM.