Dawn E. Roberts

Development and Validation of a Pregnancy Physical Activity Questionnaire

PURPOSE The effect of physical activity during pregnancy on maternal and fetal health remains controversial and studies have yet to identify the optimal dose of physical activity associated with favorable pregnancy outcomes. The aim of this study was to develop and validate a pregnancy physical activity questionnaire (PPAQ). METHODS To ascertain the type, duration, and frequency of physical activities performed by pregnant women, three 24-h physical activity recalls were administered to 235 ethnically diverse prenatal care patients at a large tertiary care facility in western Massachusetts. The relative contribution of each activity to between-person variance in energy expenditure was used to establish the list of activities for the PPAQ. The PPAQ is self-administered and asks respondents to report the time spent participating in 32 activities including household/caregiving, occupational, sports/exercise, transportation, and inactivity. To validate the PPAQ, 54 pregnant women completed the PPAQ and then wore a Manufacturing Technology, Inc. actigraph for the following 7 d. At the end of the 7-d period, the PPAQ was repeated. RESULTS Intraclass correlation coefficients used to measure reproducibility of the PPAQ were 0.78 for total activity, 0.82 for moderate activity, 0.81 for vigorous activity, and ranged from 0.83 for sports/exercise to 0.93 for occupational activity. Spearman correlations between the PPAQ and three published cut points used to classify actigraph data ranged from 0.08 to 0.43 for total activity, 0.25 to 0.34 for vigorous activity, 0.20 to 0.49 for moderate activity, and -0.08 to 0.22 for light-intensity activity. Correlations were higher for sports/exercise and occupational activities as compared to household/caregiving activities. CONCLUSIONS household/caregiving activities. CONCLUSIONS The PPAQ is a reliable instrument of physical activities during pregnancy.

Energy Expenditure of Selected Household Activities during Pregnancy

Recent epidemiologic studies have found that physical activity during pregnancy may reduce the risk of gestational diabetes mellitus (Dempsey et al., 2004; Dempsey et al., 2004) and preeclampsia (Saftlas, LogsdenSackett, Wang, Woolson, & Bracken, 2004; Sorenson et al., 2003) and help prevent excess maternal weight gain (Clapp & Little, 1995). In recognition of these findings, the American College of Obstetricians and Gynecologists (ACOG) guidelines for physical activity during pregnancy (ACOG Committee on Obstetric Practice, 2002) recommended that women without medical or obstetric complications accumulate 30 min or more of moderate intensity activity on most, if not all, days of the week. Recent studies among nonpregnant women suggested that common household chores could contribute to the time spent in moderate intensity activity, which is defined as activity requiring an energy expenditure rate of 3.0–6.0 metabolic equivalents (METs; 1 MET = 1 kcal·kg body weight-1·hr-1; Ainsworth et al., 2000). This has important implications for pregnant women, as household activity comprises a substantial portion of pregnancy physical activity and, over the course of pregnancy, accounts for a larger proportion of total activity as exercise and occupational activity generally decrease (Mottola & Campbell, 2003). Accurately measuring pregnancy physical activity is critical to assess the percentage of pregnant women meeting the ACOG guidelines. In addition, valid assessment of pregnancy physical activity is important for epidemiologic studies assessing the relationship between physical activity and maternal and fetal health outcomes. Currently, population-based surveys designed to measure compliance with these guidelines tend to rely on MET intensity estimates for household tasks provided in the Compendium of Physical Activities (Ainsworth et al., 2000). However, these MET intensity estimates are available only for nonpregnant adults and are not intended for adults with conditions that would significantly alter their mechanical or metabolic efficiency, such as pregnancy (Ainsworth et al., 2000). In addition, due to the physiologic changes that occur throughout pregnancy, energy expenditure required for specific activities may vary over the gestation period (Wolfe & Weissgerber, 2003). Therefore, relying on MET intensity values published in the compendium may lead to attenuations in observed associations between physical activity during pregnancy and maternal/fetal outcomes. To our knowledge, prior studies have not measured MET values for household tasks among pregnant women. Therefore, the primary aim of this study was to measure the metabolic cost of four commonly reported household activities (window washing, dusting, vacuuming, and laundry) during each trimester of pregnancy. Secondary goals were to: (a) assess if energy costs for these activities changed across trimesters, and (b) compare our observed values to those presented in the compendium. Energy Expenditure of Selected Household Activities During Pregnancy