Background: The significance of planned pregnancy is an accepted principle for improving the health of pregnant women; and quality of life, as one of the important indicators of women's health, is reduced in high-risk pregnancies. The aim of this research was to investigate the changes in the health related quality of life (HRQL) in low risk pregnancies in different groups based on pregnancy context. Methods: The present study was a longitudinal prospective study conducted on 250 pregnant women divided into three groups of women with planned pregnancy, unplanned/wanted pregnancy and unwanted pregnancy. Then, using WHOQOL-26 questionnaire, the quality of life of these women was measured in physical, psychological, social and environmental dimensions at the beginning of pregnancy as well as at the end of the first, second and third trimesters. Results: Based on the results, the mean score of environmental-HRQL in women with unwanted pregnancy was significantly lower than the other two groups. All dimensions on HRQL were influenced by time and group. However, changes in the physical, psychological and social dimensions of HRQL varied within the groups. Physical- HRQL changes were different within the groups. The intergroup effect on environmental dimension of quality of life changes was significant.Conclusion: It was observed in this study that HRQL in the women with unwanted pregnancy was lower than the women with planned pregnancy and those with unplanned /wanted pregnancy. Moreover, increase in gestational age would lower quality of life, but this decline had a similar pattern in different groups.