JMIR Publications

ABSTRACT

Background:

Physical activity (PA) during pregnancy is an effective and safe way to improve maternal health in uncomplicated pregnancies. However, compliance with PA recommendations remains low among pregnant women.

Objective:

The purpose of this study was to evaluate the effects of offering structured supervised exercise training (EXE) or motivational counseling (MOT) during pregnancy on moderate-to-vigorous-intensity physical activity (MVPA) level. Additionally, we investigated complementary measures of physical activity by the Pregnancy Physical Activity Questionnaire (PPAQ) and ‘gold standard’ doubly labeled water (DLW). The hypotheses were that both EXE and MOT would increase MVPA in pregnancy compared to standard care (CON), and that EXE would be more effective than MOT. In addition, the association between MVPA and the number of sessions attended was explored.

Methods:

A randomized controlled trial included 220 healthy, inactive pregnant women with a median gestational age of 12.9 (interquartile range, 9.4-13.9) weeks. 219 women were randomised to CON (n=45), EXE (n=87), or MOT (n=87). The primary outcome was MVPA (min/week) from randomization to the 29th gestational week obtained by a wrist-worn commercial activity tracker (Garmin Vivosport). Moreover, PA was measured by the activity tracker throughout pregnancy, by PPAQ and DLW. The primary outcome analysis was performed as an ANCOVA model adjusting for baseline PA.

Results:

The average MVPA (min/week) from randomization to the 29th gestational week was 33 [95% confidence interval, 18;47] in CON, 50 [39;60] in EXE and 40 [30;51] in MOT. When adjusted for baseline MVPA, participants in EXE performed 20 [4;36] min/week more MVPA than participants in CON (P=.016). MOT was not more effective than CON, and EXE and MOT also did not differ. MVPA was positively associated with the number of exercise sessions attended in EXE from randomization to delivery (P=.038). Attendance was higher for online (due to COVID-19 restrictions) compared to physical exercise training (P=.027). Adverse events and serious adverse events did not differ between groups.

Conclusions:

Offering structured supervised exercise training was more effective than standard care to increase MVPA among pregnant women, whereas offering motivational counseling on PA was not. MVPA in the intervention groups did not reach the recommended level in pregnancy. Altering the intervention into online due to COVID-19 restrictions did not affect MVPA level but increased exercise participation. Clinical Trial: The study is registered at clinicaltrials.gov (NCT03679130).