Participants: All women who seek pre-natal care at the Women's Health Clinic Barnes Jewish Hospital in St. Louis, Missouri are screened by history at the first visit for a pre-existing diagnosis of diabetes mellitus (DM) (B or C type DM). Patients with a diagnosis of pre-gestational diabetes are transferred to a specialty clinic dedicated specifically to pre-natal care for women with diabetes. All patients with on-going pregnancies and diabetes will be approached for enrollment. Non-DM subjects have a routine screen for gestational diabetes at 24 wk gestation. After a normal result, these subjects will be approached for enrollment as controls.