Associations of Circadian-Disruptive Behaviours With Plasma Glycemic Parameters and Continuous Glucose Monitoring Measures Among Pregnant Women.

AIMS: Circadian-disruptive behaviours (CDBs) may impair glucose regulation via central and peripheral clocks. This study investigated the association between CDB burden and glycemic outcomes during pregnancy. MATERIALS AND METHODS: In this prospective cohort study, 246 pregnant women were recruited at 18-24 weeks' gestation. Four CDBs were assessed using dietary records and questionnaires: eating jetlag, predominant night-eating, social jetlag, and electronic media use before bedtime. Outcomes included oral-glucose-tolerance-test (OGTT) and insulin parameters (24-28 weeks' gestation) and continuous-glucose-monitoring (CGM) metrics (18-24 weeks' gestation). Skewed outcomes were log-transformed, and associations with the number of CDBs were examined using multivariable regression. RESULTS: Compared with women without CDBs, those with two CDBs had higher fasting insulin [geometric mean ratio 1.23 (95% CI 1.02, 1.48)] and updated-homeostasis-model-assessment-of-insulin-resistance (HOMA2-IR) [1.23 (1.02, 1.47)]. Women with three or four CDBs had significantly higher fasting glucose [1.09 (1.04, 1.15)], 1-h glucose [1.17 (1.03, 1.33)], glucose area-under-the-curve [1.14 (1.03, 1.26)], and lower updated-homeostasis-model-assessment-of-β-cell-function (HOMA2-%B) [0.76 (0.62, 0.93)]. Furthermore, fetal sex modified the associations between CDBs and CGM-derived glycemic control measures, including mean glucose, glucose management indicator (GMI), and J-index (all pinteraction < 0.1). In stratified analyses, a higher cumulative CDB measure was significantly associated with higher glycemic control measures among women carrying female foetuses. CONCLUSIONS: Higher CDB burden was associated with less favourable glycemic profiles and lower HOMA2-%B during pregnancy. These findings support investigating circadian-aligned lifestyle strategies to improve maternal metabolic health. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03803345.