Table 3.

Clinical trials of Continuous Glucose Monitor Use in Pregnancies Associated with Diabetes and Effects on Maternal and Fetal Outcomes

Study	Diabetes	CGM system	No. of subjects per group	Intervention	Glucose outcomes	CGM effects on maternal and fetal outcomes
Iafusco et al.74	T1D (n = 18)	CGMS Medtronic MiniMed (n = 4) and Guardian® rtCGM Medtronic MiniMed (n = 14)	CGM: n = 18	rtCGM for 72 h during betamethasone treatment and labor and delivery	Betamethasone treatmenta: intravenous insulin adjustments based on CGM reduced glucose peaks <200 mg/dL Labor and delivery: mean glucose values of infants after birth 84 ± 16 mg/dL	• No infant respiratory distress syndrome or hypoglycemia for 72 h after birth
Stenninger et al.34	T1D (n = 17) T2D (n = 1) GDM (n = 2)	CGMS Medtronic MiniMed	CGM: n = 20	CGM during last 2 h of labor		• 9/15 (60%) infants had neonatal hypoglycemia • 5/15 (33%) infants required intravenous glucose • Area under the curve, mean glucose concentration, and cord plasma insulin levels positively correlated with intravenous glucose infusion in infants
Taslimi et al.35	T1D (n = 3) T2D (n = 1) GDM (n = 1) NGT (n = 16)	Medtronic MiniMed Paradigm®	CGM: n = 21	Blinded CGM for 3 days 26–28 weeks of gestation	15 women (5 diabetes and 10 NGT) had CGM readings >130 mg/dL, 11 had SMBG >130 mg/dL	• Positive correlation between birth weight and glucose excursions >130 mg/dL (P < 0.03) in all groups • No correlation between glucose excursions and vaginal or cesarean deliveries
Dalfra et al.37	T1D (n = 32) GDM (n = 31) NGT (n = 17)	GlucoDay®S system	CGM: n = 80	T1D: CGM for 2 days each trimester; GDM and NGT: CGM for 2 days in second and third trimesters	• MAGE significantly higher in T1D group during second and third trimester • SD, interquartile range, CONGA highest in T1D group • In second trimester, MAGE, SD, mean glucose higher in insulin-treated GDM vs. diet-controlled GDM • A1C improved significantly in T1D group during pregnancy	• No correlation between A1C and fetal growth in any group • Lower gestational age at delivery for T1D vs. other groups • Birth weight higher in GDM group
Yu et al.36	GDM (n = 340)	CGMS Medtronic MiniMed	CGM: n = 150 SMBG: n = 190	CGM for 72 h every 2–4 weeks	SD, MAGE, and mean of daily differences value significantly lower in CGM group	• Lower risk of preeclampsia and cesarean section rates in CGM group (P < 0.05) • Lower infant birth weight, less hypoglycemia, less hyperbilirubinemia, and less RDS in CGM group (P < 0.05) • More preterm births in non-CGM group (P < 0.05)
Cypryk et al.75 (Murphy76)	T1D (n = 14)	iPro®2 Medtronic	CGM + FHR monitor: n = 14	Blinded CGM and continuous cardiotocographyb in the third trimester for ≥20 h	Mean A1C <6%	• No significant decelerations in cardiotocography tracing • Elevated maternal glucose linked to increased FHR (R = 0.32; P < 0.0001) and higher chance of FHR accelerations
Law et al.38	T1D (n = 89) T2D (n = 28)	CGMS Gold Medtronic MiniMed and Guardian rtCGM Medtronic MiniMed (Sof-Sensors)	CGM: n = 117	rtCGM daily	A1C similar between groups	• LGA associated with lower and less variable glucose levels in first trimester, higher and more variable glucose levels in other trimesters

^aBetamethasone treatment was used to prevent infant respiratory distress syndrome and during labor and delivery to reduce neonatal hypoglycemia.

^bCardiotocography measures fetal heart rate as an indicator of fetal well-being.

CONGA, continuous overlapping net glycemic action; FHR, fetal heart rate; MAGE, mean amplitude of glucose excursions; NGT, normal glucose tolerance; rtCGM, real-time continuous glucose monitor; SD, standard deviation.