Background: Persistence of low fertility in many countries has been a research concern during the last two decades. Childbearing decision-making is a complex process, involving many social, economic, political, and personal factors. We aim to provide comprehensive information about the core determinants of fertility intentions Methods: Ovid, MEDLINE, EMBASE, PsycINFO, CINAHL, Web of Science, SCOPUS, and GOOGLE SCHOLAR was searched for the relevant articles published from 1946 to December 2017. The current systematic review included the original and quantitative longitudinal and cross-sectional studies in English, The subjects of the studies were men and/or women in reproductive age (men aged 18-55 and women aged 18-45). Family planning methods were available in the reference country. Studies with less than 200 participants were excluded. Results: 45 Studies included in the qualitative synthesis.310727 participants included in the analysis. All effective factors in childbearing decision- making were classified into three main categories: Individual factors, Couple Puzzle, and Contextual factors. Factors such as age, religion, education, employment, and economic conditions were classified as individual factors. We also had a special focus on couples. As fertility is a dyadic process, for more emphasis we explained the couple relationship in case of the couple puzzle. Partnership Status, Gender Role Attitudes, Couple Desire, and Partnership Quality are the main aspects of couples puzzle Social network support (interaction within networks of family and friends) and family support environment are associated with childbearing intentions among couples. Conclusion: Further collaborative efforts by researchers and funding agencies will enable us to reveal fundamental mechanisms that affect and control fertility choices at different levels. As there are limited instances of interdisciplinary studies, studying fertility would highly benefit by crossing disciplinary and geographic boundaries. Although native scholars conduct fertility investigations in each country, the majority of research on fertility does not often communicate with one another.