An alternative perspective on the Second Demographic Transition in East Asia: the relationship between pregnancy intentions and trajectories of cohabitation, marriage, and pregnancy in Japan

The Second Demographic Transition (SDT) has been a key theoretical framework for declining fertility and family changes, often marked by the decoupling of marriage and childbearing. While East Asia follows many SDT trends, its persistent link between marriage and childbearing has led to the view that East Asia is an exception. This study argues that the rise in intended premarital pregnancy within cohabitation in East Asia may reflect a trend functionally similar to the increase in nonmarital childbearing in other low fertility societies. Using data from the 14th–16th rounds of the Japanese National Fertility Survey (2010–2021), we analyze the relationship between premarital pregnancy and pregnancy intention, focusing on premarital cohabitation. Consistent with previous studies, our findings confirm that premarital pregnancies are generally more likely to be mistimed, while cohabitors are more likely to report their premarital pregnancies as intended. By highlighting the cohabitation-pregnancy-marriage sequence in Japan, this study provides a nuanced perspective on the SDT and offers insights for other societies where childbearing remains closely tied to marriage.