The following is a summary of “Continuous glucose monitoring in individuals undergoing gestational diabetes screening,” published in the OCTOBER 2023 issue of Obstetrics and Gynecology by Bartal, et al.

Inconsistencies existed among guidelines regarding the maternal hyperglycemia threshold for diagnosing gestational diabetes mellitus (GDM). For a study (June 2020 to January 2022), researchers sought to explore the association between continuous glucose monitoring (CGM) metrics and adverse outcomes in individuals undergoing GDM screening.

Participants underwent a 2-step GDM screening at ≤30 weeks of gestation, wearing a blinded continuous glucose monitoring (CGM) device (Dexcom G6 Pro) for 10 days, starting with the 50-g glucose challenge test. The primary outcome comprised adverse neonatal events (e.g., large for gestational age, shoulder dystocia, neonatal injury, respiratory distress, need for intravenous glucose treatment for hypoglycemia, or fetal/neonatal death). Secondary neonatal outcomes included preterm birth, neonatal intensive care unit admission, hypoglycemia, mechanical ventilation or continuous positive airway pressure, hyperbilirubinemia, and hospital length of stay. Secondary maternal outcomes encompass weight gain during pregnancy, hypertensive disorders of pregnancy, induction of labor, cesarean delivery, and postpartum complications. Continuous glucose monitoring metrics, including time within the target range (63–140 mg/dL), time above the target range (>140 mg/dL) expressed as a percentage of all CGM readings, and mean glucose level, were analyzed. The Youden index was used to choose the threshold of ≥10% for the time above the target range and its association with adverse outcomes.

Out of 136 participants, data from 92 individuals (67.6%) were analyzed. The 2-step screening method diagnosed gestational diabetes mellitus (GDM) in only 2 individuals (2.2%). Continuous glucose monitoring (CGM) revealed that 17 individuals (18.5%) had time above the target range (≥10%). Those with ≥10% time above the target range had a significantly higher likelihood of composite adverse neonatal outcomes than those with <10% (63% vs 18%; P = 0.001). Neonates born to individuals with ≥10% time above the target range had an increased likelihood of hypoglycemia (14.5% vs 47%; P = 0.009) and a longer length of stay (2 vs 4 days; P = 0.03) compared to those born to individuals with <10% time above the target range. No significant difference in maternal outcomes was observed between the two groups.

In the prospective GDM screening study, a cutoff of ≥10% for the time above the target range with continuous glucose monitoring was associated with a higher rate of neonatal adverse outcomes. A randomized trial comparing continuous glucose monitoring vs. 2-step screening for GDM was underway to assess the impact on reducing negative outcomes.

Source: ajog.org/article/S0002-9378(23)00252-1/fulltext