Wearable Data As Practical Proxy Of Physical Activity Levels To Estimate Energy Requirements For Pregnant People

PURPOSE: The 2023 Dietary Reference Intake (DRI) provides specific Estimated Energy Requirement (EER) equations for healthy weight gain in the 2nd and 3rd trimesters of pregnancy which are based on age, weight, height, BMI-specific energy deposition, and physical activity levels (PAL). Adherence to weight gain guidelines during pregnancy is important as excess gestational weight gain (GWG) is associated with increased risk of adverse health outcomes. However, directly measuring PAL using indirect calorimetry outside of the clinical setting is difficult, possibly resulting in erroneous estimations of the DRI. This work aims to evaluate whether steps or activity minutes from accelerometry facilitate the correct categorization of PAL in the DRI equations for pregnancy. METHODS: In this prospective, observational study in 54 pregnant females with obesity (BMI: 35.8 ± 4.7 kg/m2), PAL was measured in early (~15 weeks) and late (~36 weeks) pregnancy by 7-day doubly labeled water and basal metabolic rate. Physical activity measures (daily steps and minutes of light and medium activity) were simultaneously assessed by Actigraph Gt3x accelerometer. The range of daily steps and activity minutes was determined for each PAL category in late pregnancy. RESULTS: PAL significantly decreased (P < .001) from early to late pregnancy. The use of early pregnancy PAL in late pregnancy DRI equations resulted in significantly increased EER for inactive and low active individuals (both P < .001), in turn resulting in excess estimated GWG. The analysis of accelerometry data across PAL categories revealed large overlaps in both steps and activity minutes. Inactive PAL corresponded to 4,061-10,416 steps/day, 240-286 min of light and 111-206 min of medium activity per day. Low Active Pal corresponded to 7,402-13,033 steps/day, 220-389 min of light and 165-306 min of medium activity per day. Active PAL corresponded to 8,396-11,480 steps/day, 297-370 min of light activity and 201-252 min of medium activity per day. CONCLUSION: Accelerometry does not yield adequate data to estimate PAL. To enhance the use of DRI equations by clinicians, further investigation is needed to determine practical ways to estimate PAL. Until then, to minimize the risks associated with excess GWG, inactive PAL should be used to determine EER beyond early pregnancy. This work was funded by the NIH (R01DK099175). A. Niclou is supported by the NIH-NIDDK under Award T32DK064584