Abstract Body: Background: Hypertensive disorders of pregnancy (HDP) are primary antecedents of maternal cardiovascular morbidity during and after pregnancy. Despite increasing evidence that 24-hour movement behaviors, including moderate-to-vigorous and light-intensity physical activity (MVPA, LPA), sedentary behavior (SED), and sleep, are related to cardiovascular disease risk, associations between 24-hour movement behaviors during pregnancy and HDP are largely unknown. This study aimed to identify optimal 24-hour behavioral compositions across pregnancy trimesters associated with the lowest risk of HDP.
Methods: The Pregnancy 24/7 cohort study (N=500) quantified device-based 24-hour movement behaviors in each trimester of pregnancy and examined associations of these behaviors with HDP and other adverse pregnancy outcomes. Participants were enrolled <13 weeks gestation between 2021-2024 from three U.S. study sites (Iowa City, IA, Pittsburgh, PA, and Morgantown, WV). Movement behaviors were quantified from 7-day, 24-hour monitor wear in each trimester using the activPAL3 micro (MVPA, LPA, SED) and Actiwatch Spectrum Plus (sleep). HDP (gestational hypertension and preeclampsia) were abstracted from medical records. Adjusted compositional binomial regression models were used to predict HDP risk based on isometric log-ratio transformation of 24-hour movement behaviors by trimester. Optimal overlapping behavioral compositions were identified across trimesters.
Results: Among 470 participants with complete data, 87 (18.6%) developed HDP. SED and LPA were the main predictors of HDP risk across all trimesters. The optimal overlapping daily composition (0-5th percentile) associated with the lowest HDP risk (7.7%) consisted of 6.0 hours SED, 7.9 hours LPA, 4.0 minutes MVPA, and 10.1 hours sleep. This represents a 54% risk reduction in HDP compared to the median composition (47.5-52.5 percentile; 16.9% risk) and a 78% reduction compared to the worst composition (95-100 percentile; 34.7% risk; see Table). Risk increased exponentially among women with more than 10 hours/day of SED or less than 5 hours/day of LPA (see Figure).
Conclusions: When considering all 24-hour movement behaviors across pregnancy trimesters, SED and LPA were the strongest modifiable predictors of HDP. These findings can inform behavioral intervention targets and public health guidelines to reduce the risk of HDP.