Optimal 24-hour movement behaviour compositions across trimesters and risk of hypertensive disorders of pregnancy: the Pregnancy 24/7 cohort study

OBJECTIVES: Hypertensive disorders of pregnancy (HDP) are primary antecedents of maternal cardiovascular morbidity during and after pregnancy. Despite evidence that 24-hour movement behaviours, including moderate-to-vigorous and light-intensity physical activity (MVPA, LPA), sedentary behaviour (SED) and sleep, relate to cardiovascular disease risk, associations with HDP are unknown. This study identified optimal 24-hour behavioural compositions across pregnancy associated with lower HDP risk. METHODS: weeks gestation) and examined associations with HDP. Participants were enrolled between 2021-2024 from three US study sites. Movement behaviours were quantified from 7-day × 24-hour monitor wear using the activPAL3 micro (MVPA, LPA and SED) and Actiwatch Spectrum Plus (sleep). HDP (gestational hypertension and pre-eclampsia) was abstracted from medical records. Compositional binomial regression models predicted HDP risk based on isometric log-ratio transformation of 24-hour movement behaviours. Optimal overlapping behavioural compositions were identified by aggregating up to three repeated assessments of 24-hour data. RESULTS: Among 470 participants with complete data, 86 (18.3%) developed HDP. The optimal overlapping daily composition (0-5th percentile) associated with the lowest HDP risk (7.2%) consisted of 5.9 (5.5-6.6) hours SED, 7.9 (6.4-8.9) hours LPA, 7 (2-22) minutes MVPA and 10.1 (8.5-11.3) hours sleep. Risk increased exponentially among participants with more than 10 hours/day of SED or less than 5 hours/day of LPA. CONCLUSION: SED and LPA were the strongest modifiable predictors of HDP, independent of trimester. These findings inform behavioural intervention targets to reduce the risk of HDP.