Sayadeh Zahra Mostajabi - MSc Student of Counseling in Midwifery, Department of Midwifery, School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Iran
Nahid Jahanishoorab - a) Assistant Professor, Nursing and Midwifery Care Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran b) Department of Midwifery, School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Iran
Masoumeh Kordi - Assistant professor, Department of Midwifery, School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Iran
Habibollah Esmaily - Professor of Biostatistics, Social of Health Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran

Background & aim: Changing lifestyle before pregnancy is necessary to avoid the consequences of obesity in pregnancy. This study was performed to investigate the effect of training based on extended parallel process model (EPPM) on the weight of women with high body mass index before pregnancy. Methods: In this two-group cluster randomized trial, ۶۰ eligible women participated. Experimental and control groups were randomly selected from two comprehensive healthcare centers in Mashhad, Iran. Data collection tools included a questionnaire based on the constructs of the extended parallel process model and Baecke Physical Activity Questionnaire. The experimental group received the national nutrition guidelines based on EPPM constructs including threat as well as efficacy and the control group received the same content in a routine way. Participants' weight was measured before, two and four weeks after the intervention.Results: The two groups were homogeneous in terms of demographic and obstetric characteristics. The mean changes of construct of threat before, two and four weeks after the intervention in the experimental group compared to the control increased by ۴.۸۴ and ۳.۵۹ times, respectively, which was statistically significant (P<۰.۰۵). The mean changes of construct of efficacy before, two and four weeks after the intervention in the experimental group and also the mean weight loss four weeks after the intervention was not statistically significant.Conclusion: Further studies are needed to confirm the effectiveness of this model for weight loss and its role in increasing the perceived efficacy of overweight women at the pre-pregnancy stage.

Weight, prenatal care, Obesity, Extended parallel process model, Body mass index