Inclusion Criteria:  Maternal age >=18 at consent Singleton gestation 10w0d-14w0d gestation at the time of the Visit 1 OGTT and CGM placement according to study dating criteria Conceived using own oocyte Willing and able to wear CGM as directed and adhere to CGM instructions Planning to deliver at GO MOMs-affiliated hospital (see list of accrual sites in the protocol section "Key Roles and Contact Information").  Exclusion Criteria:  Pre-existing diabetes at enrollment Currently self-monitoring blood glucose Current use of medication with glycemic effects Fetal malformation evident at or before enrollment that is likely lethal. This includes, but is not limited to, malformations such as anencephaly, hydrops, diffuse subcutaneous edema or cystic hygroma, ectopic cordis, and encephalocele Known fetal aneuploidy based on chorionic villus sampling Participation in other research study that may modify glycemic profile or study outcomes History of bariatric surgery Extensive skin changes or diseases making CGM sensor use problematic Significant allergy to adhesive Previous participation in GO MOMs Current bulimia or anorexia nervosa Overnight shift work that alters the sleep/wake periods Hemoglobin A1c >= 6.5%, fasting glucose >= 126 mg/dL or 2 hr glucose >= 200 mg/dL noted during OGTT at 10w0d-14w0d gestation Current psychiatric illness/social situation that would limit compliance with study requirements, as determined by the site investigator