Early Pregnancy Lifestyle and Glucose Patterns: A Substudy of TOFFFY

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: 1. Do early-pregnancy chronobehavioral patterns (e.g., irregular sleep, night eating, and unstable rest-activity rhythms) relate to continuous glucose patterns measured using continuous glucose monitoring (CGM)? 2. Can early behavioral and CGM-derived measures predict glucose regulation and metabolic outcomes later in pregnancy (24-28 weeks)? 3. Does real-time self-monitoring using wearable devices and food logging improve glycemic outcomes compared to usual care? 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.