A three-armed, six-week randomized controlled trial was conducted between 16-22 weeks gestation (baseline) and 24-28 weeks gestation (final). Previously sedentary women (n=11) were randomized to one of three groups following baseline: Group 1) Reduce sedentary time (ST) by interrupting prolonged sitting (n=5); Group 2) Reduce ST via walking 30 minutes most days of the week (n=3); or Group 3) Continue with daily routines (n=3). Participants (Groups 1 and 2) received Fitbit monitors to promote physical activity (PA) behavior change.

Data was collected over a 7-day period during baseline and final. PA was assessed with activPALTM, Sensewear armband, Fitbit, and PA record. Measured weight was compared to the 2009 Institute of Medicine (IOM) recommended rate of weekly weight gain. Dietary intake was assessed using a 3-day weighed diet record. Participants underwent a 75-gram 2-hour oral glucose tolerance test (final).

No significant differences were found; descriptive results are as follows. One participant in each group decreased ST from baseline to final (-3.63%, -4.07%, -13.75%, per group, respectively). Groups 1 and 2 decreased ST in bouts > 60 minutes (152.40 + 103.34 minutes baseline, 133.18 + 19.88 minutes final; 202.55 + 60.51 minutes baseline, 175.02 + 89.84 minutes final, respectively), whereas, Group 3 increased (203.95 + 92.89 minutes baseline, 224.69 + 132.18 minutes final). A moderate effect size was found for reducing prolonged ST between intervention groups and Group 3 (0.66). Group 1, decreased moderate vigorous physical activity (MVPA) from baseline (132 + 96.16 minutes) to final (40.5 + 34.64 minutes). Groups 2 (16.66 + 22.30 minutes baseline; 53.66 + 85.27 minutes final) and 3 (UC; 73.33 + 62.26 minutes baseline; 84.33 + 84.67 minutes final) increased. A small effect size was demonstrated between intervention groups and Group 3 (0.48). Groups 1 and 2 met the intervention goal 58.4-98.8% and 0-213% of the time, respectively. A positive relationship for increased ST, higher fasting, 60, 120-minute blood glucose levels and increased calorie consumption was found. Based on the IOM guidelines, one participant gained less, one met and six exceeded recommendations. Based on preliminary data, finding effective strategies to decrease ST during pregnancy remains important.