Investigating Markers of Energy Metabolism in Pregnant Women With Insulin Resistance

The investigators seek to examine the metabolic changes that occur amongst obese and lean pregnant women with normal glycemic control as well as pregnant women with diabetes mellitus (gestational diabetes and pre-existing type 2 diabetes mellitus) compared to non-pregnant age matched controls. Given the adaptive tendency of the maternal body to use alternative energy sources such as ketones and free fatty acids rather than glucose and to shunt glucose and amino acids to the fetus, the investigators hypothesize that the amino acid and fatty acid profile will be reflective of this adaptive change and that maternal insulin resistance will result in alterations in this pattern in both the plasma and CSF. Furthermore, the investigators also hypothesize that maternal degrees of insulin resistance will also be reflected in CSF hormonal changes.