SAT134 CGM Use During Pregnancy Complicated By CF-Induced Diabetes
Authors: Mazori Alon Y , Markovic Emily S , Levy Carol J 
Published: October 2023

Abstract
Disclosure: A.Y. Mazori: None. E.S. Markovic: None. C.J. Levy: Advisory Board Member; Self; Dexcom, Eli Lilly & Company. Research Investigator; Self; Abbott Laboratories, Insulet Corporation, Tandem Diabetes Care, Dexcom.
Introduction: Glycemic control remains challenging in pregnancies complicated by diabetes mellitus. Strict glycemic targets are required to optimize maternal and neonatal outcomes, but euglycemia is hindered by fluctuating insulin sensitivity and the need for frequent blood-glucose monitoring (BGM). Consensus guidelines recommend therapeutic continuous glucose monitoring (CGM) for pregnant and nonpregnant individuals with type 1 and type 2 diabetes, but current data support therapeutic CGM use in cystic fibrosis (CF)-related diabetes (CFRD) only outside of pregnancy. We report the case of a patient with CFRD who achieved recommended glycemic targets with a therapeutic CGM during a singleton pregnancy. Methods: A case report and literature review are presented. Results: A 32-year-old nulliparous woman with CF became pregnant via frozen-embryo transfer. Prior CF complications included CFRD, pancreatic insufficiency, and recurrent pancreatitis. A therapeutic Dexcom G6 CGM and intermittent BGM were used to monitor glycemic control before and during pregnancy; sensor use exceeded 96%. Pressure-induced sensor attenuations yielded sporadic hypoglycemic values discordant with simultaneous BGM. CGM analysis for the 90 days preceding conception revealed: time in range of 63-140 mg/dL (TIR) was 90.8%, time above range (TAR) 6.3%, and time below range (TBR) 2.9%. Throughout pregnancy, TIR was 92.9%, TAR 3.4%, and TBR 3.6%; no severe hypoglycemia occurred. Daytime (6AM to midnight) and nighttime hypoglycemia were 4.6% and 2.2%, respectively. In the first trimester, TIR was 90.8%, TAR 3.7%, and TBR 5.5%. During the second trimester, the patient achieved TIR 94.2%, TAR 2.6%, and TBR 3.2%. In the third trimester, TIR was 95.7%, TAR 0.9%, and TBR 3.4%. The pregestational CFRD regimen consisted of insulin glargine 12 units and lispro 3-8 units. The basal-insulin dose was 10 units at 13 weeks’ gestation, 9 units at 27 weeks’ gestation, and 8 units at 38 weeks’ gestation. The prandial-insulin doses varied between 1.5-5 units at 13 weeks’ gestation, 0-7 units at 27 weeks’ gestation, and 0-5 units at 38 weeks’ gestation. After an uncomplicated vaginal delivery at 38 weeks and six days’ gestation, maternal fasting hypoglycemia occurred after one dose of glargine 3 units. Euglycemia was obtained without basal, prandial, or correctional insulin. The neonate experienced mild hypoglycemia that resolved with oral glucose gel and feeding. The neonate was neither macrosomic nor large for gestational age (birth weight, 3.54 kg, 71st percentile) and did not require intensive-care unit management. Both the patient and neonate were discharged on postpartum day two. Conclusion: Therapeutic CGM use in a pregnancy complicated by CFRD was effective for maternal and neonatal outcomes. Further study is warranted to examine CGM use and efficacy in this population.
Presentation: Saturday, June 17, 2023