Diabetes mellitus affects roughly 8% of pregnancies and is associated with significant perinatal and maternal morbidity. Increasing numbers of women are either entering pregnancy with a continuous glucose monitor (CGM) or are initiating use during pregnancy, with data emerging suggesting improved outcomes among those using CGM. Since the introduction of CGM in the late 1990s, there has been slow acceptance of their validation and use in the inpatient setting. The investigators propose an observational prospective cohort study to analyze the correlation of CGM data with traditional capillary glucose readings in the intrapartum and postpartum settings.

Inclusion Criteria:

• Age 18-50 years
• Women with a viable singleton or twin intrauterine pregnancy between 22 5/7 and 41 6/7 weeks gestation based on the best obstetric estimate by ACOG criteria
• Diagnosis of insulin-dependent pregestational diabetes mellitus (type 1 or type 2 diabetes)
• Planning to deliver at OSU Wexner Medical Center
• Able to understand the study, and having understood, provide written informed consent in English

Exclusion Criteria:

• Gestational diabetes mellitus, Maturity Onset Diabetes of Young, and Cystic Fibrosis Related Diabetes
• Abnormal obstetrical ultrasound suspicious for major congenital abnormality
• Known or suspected fetal aneuploidy (by either CVS, amniocentesis, or cell-free DNA)
• Participation in another trial that may influence the primary outcome, without prior approval
• Participation in this trial in a prior pregnancy
• Higher order pregnancy
• History of severe skin allergy to adhesive products or CGM within the previous 3 months

Pregnant woman

Women ages 18-45 who are pregnant

No IPD will be shared with outside investigators