Blossom Project 2: Longitudinal assessment of physical activity, sedentary behavior, diet quality, and weight gain during pregnancy

The benefits of physical activity (PA) during pregnancy have been well documented, but little is known about the contribution of activity sub-components including sleep, sedentary, light, moderate, and vigorous activity on gestational weight gain (GWG). Additionally, the relationship between diet quality and GWG has yet to be determined. A prospective, longitudinal study was conducted during 2 nd and 3 rd trimester to objectively quantify and identify modifiable aspects of total PA including sleep, sedentary, light, moderate, and vigorous activity, and dietary intake. Participants (n=46) wore a SenseWear® Armband and an activPAL TM activity monitor for seven consecutive days during which a weighed 3-day diet record was also completed. Paired t-tests were used to compare data across pregnancy and multiple regression was used to identify predictors of GWG. Time spent in nighttime sleep, naps, sedentary behavior (SB), and moderate PA did not change across pregnancy while light and vigorous PA significantly decreased. During both the 2 nd and 3 rd trimester women spent an average of 75% of time awake in sedentary behavior even though 65% (week 18) and 61% (week 35) met the prenatal PA recommendations. Additionally, prediction equations showed positive correlations between protein intake (P = 0.071) and MET-minutes (P = 0.038) with GWG at week 18 (R 2 = 0.29, rMSEP = 2.18); and between carbohydrate intake (P = 0.098) and MET-minutes (P = 0.038) with GWG at week 35 (R 2 = 0.19, rMSEP = 3.99). Due to the large portion of the day spent in SB regardless of whether or not prenatal PA recommendations were met, and the observed relationship between total activity (MET-minutes) and weight gain across pregnancy, an