A secondary analysis found that reduced time in target glucose range during labor was associated with increased adverse neonatal outcomes in gestational diabetes.
Maintaining optimal glucose levels during labor was associated with improved neonatal outcomes among patients with gestational diabetes mellitus (GDM), according to a secondary analysis published in Pregnancy. The study found that reduced time within the target glucose range during labor correlated with higher rates of adverse neonatal outcomes, highlighting the potential importance of intrapartum glycemic control.1
GDM affects approximately 6% to 9% of pregnancies in the United States and is linked to a range of maternal and neonatal complications, including hypertensive disorders, cesarean delivery, and increased risk of type 2 diabetes later in life. Neonates born to patients with GDM are also at increased risk for conditions such as hypoglycemia and respiratory distress, and admission to the neonatal intensive care unit (NICU). Neonatal hypoglycemia alone has been reported in up to 45% of cases and, in severe instances, may lead to seizures or long-term complications.1,2
While maintaining glucose targets during pregnancy has been shown to improve outcomes, the role of intrapartum glucose management has remained unclear. Prior research has produced mixed findings, and clinical practice varies widely between institutions. This uncertainty has limited the ability to standardize care during labor for patients with GDM.1
In the study, researchers conducted a secondary analysis of a randomized trial comparing continuous glucose monitoring (CGM) with traditional capillary blood glucose monitoring in patients with GDM. The analysis focused on 59 participants who had CGM data available during labor and had undergone a trial of labor.
The primary outcome was a composite of adverse neonatal events, including hypoglycemia, hyperbilirubinemia, and respiratory distress syndrome, or NICU admission. Investigators evaluated intrapartum glucose control using CGM-derived metrics, including mean glucose levels and percent time in range, defined primarily as glucose levels between 70 mg/dL and 120 mg/dL.
The findings showed that participants whose pregnancies were complicated by adverse neonatal outcomes spent significantly less time within the target glucose range during labor compared with those without complications (62.7% vs 80.7%, P = .012). They also spent significantly more time above the target range (26.7% vs 10.6%, P = .007).
Although mean glucose levels were higher in the adverse outcome group (103.9 mg/dL vs 94.6 mg/dL), this difference did not reach statistical significance (P = .059). The analysis also identified a weak-to-moderate positive correlation between antenatal and intrapartum glucose control, suggesting that patients with better glucose management during pregnancy tended to have better control during labor.
The authors noted that patients in the adverse outcome group appeared to have a higher-risk obstetric profile, and the relatively small sample size limited the ability to adjust for potential confounders. As a result, residual confounding could not be ruled out as an explanation for the observed associations.
Despite these limitations, the study contributed to a growing body of evidence supporting the use of CGM in pregnancy. With increasing adoption of CGM following regulatory clearance for use in pregnancy in recent years, clinicians may have greater opportunities to monitor and optimize glucose levels in real time.
The researchers suggested that maintaining glucose levels within the 70 to 120 mg/dL range during labor may represent a meaningful target for reducing neonatal risk. However, further research is needed to confirm this threshold. Current guidelines recommend maintaining glucose levels below 110 mg/dL during labor, but recent evidence has questioned whether tighter control provides additional benefit specifically for patients with GDM.
“As CGM use becomes more prevalent among patients with GDM, this study represents a meaningful addition to the literature in this population,” the authors wrote. “Obstetric clinicians will be tasked with more frequent interpretation of CGM data to guide patient care, and this includes the labor and delivery setting. Greater clarification of this target utilizing CGM metrics is a logical next step. Until then, patients with GDM may benefit from prioritizing euglycemia intrapartum just as euglycemia is prioritized antepartum, given the observed association between suboptimal glycemic control prior to delivery and adverse neonatal outcomes.”
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