Association of duration of intrapartum maternal hyperglycemia in well-controlled gestational diabetes mellitus women and risks of neonatal hypoglycemia: a retrospective cohort study.

Objectives: Achieving intrapartum euglycemia is recommended to reduce the risk of neonatal hypoglycemia. However, recent research relating the association of maternal intrapartum glucose and neonatal hypoglycemia showed conflicting results, particularly in women with gestational diabetes mellitus (GDM). We aimed to assess the association between intrapartum maternal hyperglycemia and neonatal hypoglycemia in women with GDM.

Methods: A retrospective cohort study was conducted among 508 pairs of women with GDM and their neonates in Peking University First Hospital from 18 October 2020 to 18 October 2021. Our exposure was the maternal time above range (TAR) for glucose during labor, defined as the duration when glucose levels exceeded 126 mg/dL. We split the participants into four groups according to their TAR quantiles and employed natural spline regression using the LOESS method to illustrate the relationship between maternal TAR and neonates' lowest glucose level within 24-h postbirth.

Results: Of the 508 women included, 37.8% (192/508) experienced hyperglycemia with a TAR over 25%. TAR quantiles were not significantly associated with neonates' lowest glucose levels (adjusted coefficients [95%CI], Q1: reference, Q2: 0.24 [-0.04, 0.54], Q3: 0.11[-0.21, 0.43], Q4: 0.18[-0.15, 0.52]). However, increased TAR >100 mg/dL resulted in higher neonatal glucose values (adjusted coefficients [95%CI]: Q1: reference, Q2: 0.33 [-0.04, 0.71], Q3: 0.47 [0.11, 0.82], Q4: 0.35 [0.07, 0.63]). Moreover, maternal hypoglycemia was association with neonatal hypoglycemia (adjusted coefficients [95%CI]: -0.67 [-1.15, -0.18]).

Conclusion: Intrapartum glycemic control may be considered not as critical, when the overall glucose control throughout pregnancy is optimized. As neonatal hypoglycemia shows association with maternal hypoglycemia, which may be induced by strict intrapartum glycemic control, a less stringent intrapartum glucose target is preferred.