A feasibility study of activity tracking devices in pregnancy

Abstract

Background: We aimed to evaluate the feasibility of using an activity-tracking device (ATD) during pregnancy and compare self-reported to ATD-calculated energy expenditure in a 2-phase study.

Methods: (Phase 1) Twenty-five pregnant women were asked about exercise, computer use, smartphone ownership, and ATD attitudes. Descriptive statistics were reported. (Phase 2) Women ≥18 years, smartphone owners, < 16-weeks gestation, and without exercise restrictions were approached to participate in 2016-2017. Women received instructions to wear and sync the ATD daily. We assessed protocol adherence and satisfaction via surveys at 36-weeks and used mixed models to assess the relationship between gestational age and ATD data. Energy expenditure from the Pregnancy Physical Activity Questionnaire (PPAQ) was compared to ATD-calculated energy expenditure.

Results: (Phase 1) Walking was the most common exercise; 8% did not perform any activity during pregnancy. All women had internet access and owned a smartphone. Women stated they would wear the ATD all the time during a pregnancy (88%), with the intent to improve their health (80%). (Phase 2) The characteristics of the 48 women were: pre-pregnancy BMI 28, 62% non-Hispanic black, 62% multiparas. Of the 18 women who completed the 36-week survey, only 56% wore the ATD daily, 33% had a lost or broken ATD, and 17% had technical problems; however, 94% enjoyed wearing it, 94% would recommend it to a pregnant friend, and 78% thought it helped them reach activity goals. According to ATD data, the median number of active days was 41 (IQR 20-73) and the median proportion of active days out of potential days was 22% (IQR 11-40). As gestational age increased, mean log steps decreased, active minutes decreased, and sedentary hours increased in unadjusted and adjusted models (P < 0.05 all comparisons). There were no differences in mean energy expenditure (MET-h/week) estimated by PPAQ or ATD data at 28 weeks gestation [212 (22-992 range) vs. 234 (200-281 range), P = 0.66] and at 36 weeks [233 (86-907 range) vs. 218 (151-273 range), P = 0.68]).

Conclusions: Women reported high motivation to wear an ATD and high satisfaction with actually using an ATD during pregnancy; however adherence to the study protocol was lower than expected and ATD technical problems were frequent.

Keywords: Feasibility study; Physical activity; Pregnancy; Prenatal care.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1

Active days of activity tracking device use, defined as at least 1000 steps/day (red bars) as a proportion of total potential active days (blue bars) from date of enrollment to date of delivery for 25 participants who did not report permanent activity tracking device or cellphone problems (e.g., lost or broken device or charger, loss of cellphone access). The median proportion of active days was 22% (IQR 11.0,40.0)

Fig. 2

Mean (blue bars) and range (red bars) of (a) steps, (b) active minutes, and (c) sedentary hours for 29 participants who wore the activity tracking device consecutively for the first seven days. The mean steps per day were 7050 (range 2286–15,133), active minutes per day were 262 (range 100–395), and sedentary hours per day were 12.4 (range 8.5–19.3)

Fig. 3

Longitudinal modeling for activity tracking device data with predicted (a) logarithmic steps (β Gestational week = − 0.006, P-value = 0.004), (b) active minutes (β Gestational week2 = − 0.133, P-value = 0.03), and (c) sedentary hours (β Gestational week = 0.15, P-value < 0.001) as denoted by black lines with 95% CI (shaded area) plotted against gestational age with p < 0.05 for change over time for all comparisons