Excessive gestational weight gain (GWG) during pregnancy is a major public health concern. Studies have reported more than 70% of pregnant women gain excessive weight which may pose increased maternal and fetal risks. Little is known about the relationships of GWG to behavioral factors (i.e., physical activity, sleep, social support) and maternal mental health (i.e., stress, anxiety, depression) during pregnancy. This descriptive, cross-sectional study explored the relationships of GWG to behavioral factors and maternal mental health during pregnancy. Secondarily, this study described the preferences, uses of, and interests in alternative approaches as well as the mental health differences between users and non-users of alternative approaches during pregnancy. A national survey was administered to women ≥8 weeks pregnant, ≥18 years old, and residing in the United States (N=968). Bivariate correlations were used to determine relationships between GWG and variables of interest. Independent t-tests were used to observe mental health differences between users and non-users of alternative approaches. Data were analyzed throughout pregnancy and by trimester. Throughout pregnancy, significant relationships were found in GWG to stressful events (r=-.112, p<.01), depression (r=.066, p<.05), mindfulness (r=-.067, p<.05), and sleep (r=.089, p<.01). When GWG was assessed by trimester, stressful events were significant in the second (r=-.216, p<.01) and third trimesters (r=-.085, p<.05). Depression remained positively related to GWG in the first (r=.409, p<.01) and second trimesters (r=.162, p<.01). A positive relationship emerged between GWG and anxiety in the first trimester (r=.340, p<.01) and physical activity became significant in the second (r=-.136; p<.05) and third trimesters (r=-.100; p<.05). Mindfulness was the only variable significantly related to GWG throughout all time points. Mean anxiety (d=.236; p=.001) and depression (d=.265; p<.001) scores were significantly lower in users compared to non-users of alternative approaches throughout pregnancy and when assessed by trimester anxiety (d=.424; p=.001) and depression (d=.526; p<.001) were significant in the second trimester. This study provides a framework for future analyses in GWG and maternal mental health. The information presented here may inform future interventions to test the effectiveness of alternative approaches to simultaneously manage maternal mental health and GWG due to the integrative nature of alternative approaches.