The Korean government has been making long-term responses to the problem of low fertility by establishing the Basic Plan for a Low-Fertility and Older Society every five years since 2006, but the trend of low fertility is intensifying. Under these circumstances, this paper aims to reveal which discourses on fertility have been mainstreamed and which have been marginalized in the Korean media over the past two decades. To this end, we analyzed the frequent words that appeared in the 'low birthrate' reports of two representative mainstream newspapers, the Dong-A Ilbo and the Kyunghyang Shinmun, and conducted a textual analysis of the main opinion articles in which these words appeared. The results showed that the issue of low birthrate was covered most frequently around 2018, when the total fertility rate dropped to less than 1. In contrast, policy coverage was not particularly active during the years when the new basic plan was announced or the presidential election. In terms of the keywords and content that were actively covered in both newspapers, the Dong-A Ilbo emphasized private participation in solving the low birthrate problem from the beginning, and was critical of the free childcare debate. The Kyunghyang Shinmun, in common with the Dong-A Ilbo, covered jobs as the most important issue from the beginning, and in that context, it tended to focus on the poor economic conditions of the younger generation, unlike the Dong-A Ilbo, which emphasized economic revitalization. Over time, both media have tended to reiterate the traditional discourse of emphasizing economic factors, despite the complexity of the problem's causes and solutions. This study suggests that Korean mainstream media need to pay attention to the multilayered aspects of the declining birthrate and present more diverse diagnoses and solutions.