Purpose:
Determining the motives for and barriers to physical activity (PA) during pregnancy may help to promote PA throughout gestation. Therefore, the purpose of this study was to describe the most frequent motives for and barriers to maternal exercise by trimester in exercising and non-exercising women who belonged to a health club.

Methods:
A retrospective, online survey was available to the participating women. They stated the top 3 motives and barriers for exercise during each trimester. Frequencies and chi-squared test proportions were calculated.

Results:
The study involved 295 women. The most commonly reported motives for exercise during each trimester was to stay healthy (37.4%, 35.5%, and 32.9%, respectively) and to control weight (19.8%, 27.1%, and 25.5%, respectively). The most commonly reported barrier to exercise was lack of energy/tiredness in all trimesters (27.0%, 18.9%, and 19.4%, respectively). During trimesters 1 and 3, trimester-specific barriers such as pregnancy-related illness (18.5%) and exercise being too uncomfortable (17.2%) emerged, respectively.

Conclusions:
PA motives and barriers did not change statistically significantly by trimester regardless of exercise status (p > 0.05). Although not explored in this study, tailoring PA messages to overcome the most salient barriers in each trimester, such as education regarding how to modify PA in the third trimester to make exercise more comfortable, may be more effective than promoting general health benefits of PA during pregnancy.