An interventional study of Continuous glucose monitor (CGM) and Wrist actigraphy device in Continuous Glucose Monitoring, Diabetes, Gestational and Diet During Pregnancy, sponsored by KK Women's and Children's Hospital. Recruiting at 1 site in Singapore. Open to female participants aged 21 Years to 39 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by KK Women's and Children's Hospital · Not applicable, Interventional, and Prevention
The goal of this clinical trial is to examine how daily behavioral patterns in early pregnancy, including sleep, physical activity, and meal timing, influence continuous glucose dynamics and subsequent risk of gestational diabetes mellitus (GDM) in pregnant women without pre-existing diabetes.
The main questions it aims to answer are:
This study is a prospective, nested randomized pilot trial embedded within the ongoing Towards Optimal Fertility, Fathering and Fatherhood studY (TOFFFY) cohort (NCT06293235) at KK Women's and Children's Hospital, Singapore. A total of 140 pregnant women without pre-existing diabetes, recruited at ≤13 weeks gestation, will be randomized in a 1:1 ratio to either a pilot arm (wearable-based self-monitoring) or a control arm (usual care).
Participants in the pilot arm (n=70) will undergo intensive behavioral and metabolic monitoring over a 14-day period in early pregnancy, including continuous glucose monitoring using a CGM device, wrist actigraphy to assess sleep-wake and rest-activity patterns, and an AI-supported mobile application to record meal timing and dietary intake. Participants will have real-time access to their glucose data and behavioral feedback, enabling self-monitoring and potential behavioral adjustments.
Circadian disruption during pregnancy is increasingly recognized as an important, yet understudied, contributor to impaired glucose regulation and gestational diabetes mellitus (GDM). Emerging evidence suggests that nocturnal eating, irregular sleep timing, reduced rest-activity rhythm (RAR) stability, and greater behavioral variability may impair glucose homeostasis through pathways involving reduced insulin sensitivity, altered β-cell stress, and inflammation.
Most studies assess chronobehaviors using questionnaires, which are limited by recall bias and poor temporal granularity. Recent technological advances enable high-resolution measurement of circadian and metabolic physiology using wrist actigraphy and continuous glucose monitor (CGM). These tools allow objective quantification of sleep timing, RAR, activity fragmentation, and 24-hour glycaemic patterns. Integrating these data in early pregnancy may enable earlier identification of at-risk women, allowing intervention before the onset of overt hyperglycaemia.
The ongoing TOFFFY study (NCT 06293235) provides a unique opportunity to embed such a pilot study among well-phenotyped Singaporean pregnant women. Leveraging this cohort will support mechanistic insights into the interplay between circadian rhythms, meal timing, and glucose regulation, and provide preliminary data to power a larger mother-fetus chronometabolic project. Findings from this pilot will provide high-resolution insight into how early-pregnancy circadian, behavioral, and glycemic patterns interact to shape metabolic physiology. By capturing glucose responses such as glucose AUC, insulin resistance, and C-peptide, the study will identify early mechanistic pathways through which chronobehavioral disruption contributes to dysglycemia.
877 studies on the registry are indexed under Diabetes, Gestational; 203 are open to participants now.
This study's planned enrollment of 140 is above the median of 110 across 564 interventional studies indexed under Diabetes, Gestational.
Browse Diabetes, Gestational studies →KK Women's and Children's Hospital is the lead sponsor of 137 studies on the registry; 33 are open to participants now.
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Exclusion Criteria:
Participants in this arm (n=70) will undergo a 14-day monitoring period in early pregnancy (≤13 weeks gestation). Participants will have real-time access to their glucose data and food logging feedback, enabling self-monitoring and potential behavioural adjustments. Participants will also continue to receive routine antenatal care and standard clinical assessments.
Device: Continuous glucose monitor (CGM) · Device: Wrist actigraphy device · Behavioral: AI-based dietary and meal timing logging mobile application
Participants (n=70) receive routine antenatal care only, with no additional devices, monitoring, or feedback introduced by the study.
Participants will wear a continuous glucose monitor for 14 days in early pregnancy.
A wrist actigraphy device will be used to assess sleep-wake patterns and physical activity over 14 days.
Participants will record their dietary intake, meal timing logging, and feedback-based self-monitoring using an AI-based food logging mobile application.
24-hour glucose area under the curve (AUC)
Continuous glucose monitor (CGM) will be used to assess 24-hour glucose exposure, expressed as area under the curve (AUC) (unit: mmol/L h). Higher AUC values indicate greater overall glucose exposure and poorer glycemic control.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Nocturnal glucose levels
CGM will be used to assess mean nocturnal glucose levels during the sleep period. The ideal nocturnal glucose range is 3.9-10mmol/L). Higher values indicate poorer nocturnal glycemic control.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Glycemic variability - standard deviation (SD)
CGM will be used to assess glycemic variability using the standard deviation (SD) of glucose values (unit: mmol/L), reflecting the dispersion from the average blood glucose level. Higher values indicate greater glycemic variability and poorer glycemic control.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Glycemic variability - coefficient of variation (CV)
CV is an accepted index for evaluating within-day glycemic variability, where CV = (SD) / (mean glucose) × 100%. Higher values indicate greater glycemic variability and poorer glycemic control. A CV of ≥36% is commonly used to define high glycemic variability.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Rest-activity rhythm (RAR) - intra-daily variability (IV)
Wrist actigraphy will be used to derive RAR by calculating the intra-daily variability (IV). IV reflects the degree of fragmentation in circadian activity patterns by assessing fluctuations in activity frequency and intensity within a given time period, capturing the extent of transitions between periods of rest and activity over time. IV values range from 0 to 1. Higher IV scores indicating poorer outcomes with greater disruption and fragmentation of the RAR.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Rest-activity rhythm (RAR) - inter-daily stability (IS)
Wrist actigraphy will be used to derive RAR by calculating the inter-daily variability (IS). IS reflects the stability of 24-hour circadian activity variations and the balance between RAR and the circadian cycle. IV values range from 0 to 1. IS values close to 1 indicating a better RAR outcome with greater rhythm stability.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Chrononutrition behavior - meal timing
AI-based food logging will be used to assess meal timing, defined as the timing of caloric intake, expressed as clock time of energy consumption. Later or more irregular intake timing indicates less favorable chrononutrition alignment.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Chrononutrition behavior - eating jetlag
AI-based food logging will be used to assess eating jetlag, defined as the difference in timing of the caloric midpoint between weekdays and weekends (unit: hours). Higher values indicate greater circadian misalignment in eating behavior.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Chrononutrition behavior - frequency of night-eating
AI-based food logging will be used to assess frequency of night-eating episodes, defined as the number of eating events occurring during the biological night or habitual sleep period. Higher night-eating frequency indicates poorer chrononutrition behavior.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Glucose tolerance status during pregnancy
Glucose tolerance status will be assessed using a 75 g oral glucose tolerance test (OGTT), which reflects dynamic glucose response at 0, 60, and 120 minutes (unit: mmol/L). Higher values indicate poorer glucose tolerance. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Total glycemic exposure during pregnancy
Total glycemic exposure during the 75 g OGTT will be calculated as area under the glucose curve (unit: mmol/L h). Higher values indicate poorer glucose tolerance. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Glycemic marker - fasting insulin
Serum insulin concentration measured in blood (unit: pmol/L, SI unit) following the 75 g OGTT at 0, 60, and 120 minutes. Higher values indicate greater circulating insulin levels. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Glycemic marker - C-peptide
C-peptide concentration is assessed (unit: pmol/L, SI unit) following the 75 g OGTT at 0, 60, and 120 minutes. Higher values indicate increased endogenous insulin secretion. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Maternal glycemic control index - Homeostatic Model Assessment for Insulin Resistance (HOMA-IR)
HOMA-IR is derived from fasting glucose and fasting insulin to measure insulin resistance. Higher values indicate more insulin is needed to maintain glucose levels. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Glycemic control index - Homeostatic Model Assessment for Beta Cell Function (HOMA-β)
HOMA-β is derived from fasting glucose and fasting insulin to assess the function of beta cells in the pancreas, which are responsible for producing insulin. Higher value indicates better beta-cell functionality, while a lower value suggests impaired beta-cell function, which can be a sign of insulin resistance or diabetes. The glycemic outcomes will be compared between participants receiving the pilot intervention and those receiving usual care.
Time frame: From 24 weeks till 28 weeks of gestation
Sleep timing
Wrist actigraphy will be used to assess sleep timing, including sleep onset time and wake time (unit: clock time, hh:mm). Later sleep timing indicates delayed circadian phase. Changes across the monitoring period will be evaluated to assess potential behavioral effects of real-time self-monitoring.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Physical activity level
Wrist actigraphy will be used to assess physical activity pattern based on daily step counts. Higher values indicate greater physical activity levels. Changes across the monitoring period will be evaluated to assess potential behavioral effects of real-time self-monitoring.
Time frame: From enrollment in first trimester (≤13 weeks gestation), over 14 days
Plan to share: No — Individual participant data will not be shared due to ethical and privacy considerations, as the dataset contains sensitive health and behavioural information that could potentially allow participant re-identification.
No publications or documents are linked to this record.
Started May 2026 (actual). Primary completion is estimated for Apr 2027, 11 months after the start.
Of 307 non-industry interventional studies with no phase under Diabetes, Gestational, half reached primary completion within 29 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 48. This study's planned 11 months is below that.
Counting every sponsor, half of 310 studies reached it within 28 months; a quarter within 13 and three quarters within 48.
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