Effectiveness of Interventions to Promote Physical Activity During Pregnancy

Interventions that decrease sedentary behavior (SB) and improve physical activity (PA) provide a path to improve maternal health and infant outcomes. Sedentary behavior (sitting, reclining, or lying while awake; activity energy expenditure of 1.5 metabolic equivalent of task [MET]) during pregnancy is a modifiable factor associated with adverse maternal health (e.g., psychological distress, gestational weight gain, impaired sleep, impaired glucose regulation, hypertension) and infant (e.g., earlier gestational age at birth, macrosomia [>4,000 grams]) health outcomes. Pregnant women are more sedentary than the average U.S. reproductive age woman (>12 hours/day vs. <8 hours/day), placing pregnant women in the highest sedentary risk category. Most pregnant women do not meet pregnancy guideline recommendations for moderate-intensity PA of 150 minutes/week. Improved PA among pregnant women is crucial to improve maternal health outcomes.

Using a behavioral clinical trial design, 60 pregnant women with singleton pregnancy (e.g., no twins) will be recruited at 8-12 weeks gestation (T1) from prenatal clinics. Participants will engage in the Sit Less, Move More (SLMM) intervention. At T1, participants complete questionnaires about SB and PA habits, weekly PA, and personal factors (e.g., demographics) and wear an ActiGraph PA tracker for 2 weeks. At Week 3, Fitbits and a SB and PA prescription will be given to participants with information on safe recommended pregnancy PA and health risks of SB while pregnant; have PA coaching (virtual 1:1 session, weekly texts); exercise with a partner at least 4 days/week; and receive Fitbit prompts for activity when SB ≥50 minutes while awake is detected. Participants also: 1) complete questionnaires at T2 (18-22 weeks) and T3 (28-32 weeks); and 2) wear a Fitbit throughout the study from Study Week 3 to 32 weeks gestation. We aim to: Aim 1) Determine the feasibility of recruitment, retention, adherence and acceptability of the SLMM intervention for pregnant women; and Aim 2) Obtain estimates of the efficacy of the SLMM intervention on daily SB, SB habit reversal, and weekly PA and PA habit for pregnant women.

The study will allow the investigators to modify SLMM, estimate its behavior change efficacy and lead to formal efficacy testing with an R01 submission to better understand pathways to improve SB and PA amongst pregnant women. This study fosters the NICHD mission to improve reproductive health and support enhanced maternal health and birth outcomes.

Eligibility Criteria

• 18 to 45 years old
• speak English
• 8 to 12 weeks pregnant (gestation)
• singleton pregnancy (no twins or more)
• self-report less than 150 minutes/week of moderate-intensity physical activity
• have or are willing to identify a physical activity partner
• have a cell phone with the capacity for Fitbit application (app.); secure transmission of Fitbit data; receive coaching text messages or, if not, a computer they can use to synch the fitbit, send data, and receive email messages in lieu of texts.

Exclusion criteria

• Women with physical activity restrictions (e.g., placenta previa) that prevent them from completing ACOG recommended pregnancy physical activity