An Explanatory Model of Weight Management Behaviors during Pregnancy: a Cross-Sectional Study.

Purpose: This study aims to create and validate a model explaining gestational weight gain and management behaviors using Ajzen's Theory of Planned Behavior, assessing the model's fit with actual data and examining the influences of various factors.

Methods: Employing a correlational research design, data were collected and analyzed from 396 primigravida who were at least 36 weeks and agreed to participate in the study from April 15, 2022 to August 15, 2022 through an online questionnaire. SPSS 26.0 was used to analyze the general characteristics of participants, descriptive statistics of variables, reliability of tools, and correlation of variables. AMOS 28.0 was used to verify hypothesis and to assess the fitness of hypothetical models.

Results: Modified model fitness was χ²/df = 3.29, GFI = .93, SRMR = .06, RMSEA = .08, CFI = .92, TLI = .88, PNFI = .62. All of hypothesis were statistically significant. The more positive attitude toward weight management behaviors (β = .52, p < .001), the higher perceived behavioral control (β = .21, p = .011) and subjective norms (β = .31, p = .034) were shown to have a significant effect on weight management behavioral intentions. They explained 77% of the variance in weight management behavioral intention. Weight management intentions (β = .63, p < .001) and perceived behavioral control (β = .52, p = .003) significantly influenced weight management behaviors, explaining 79% of the behavior variance. Enhanced weight management behaviors significantly reduced gestational weight gain accounting for 31% of the variance in gestational weight gain (β = -.56, p < .001).

Conclusions: Establishing a nursing intervention strategy that addresses attitude, subjective norms, and perceived behavioral control is crucial, as these factors enhance weight management intentions and behaviors, thereby facilitating appropriate gestational weight gain and reducing pregnancy complications.