Converging fertility trajectories across developed countries, 2010–2020: implications for public health policy

Fertility decline has emerged as a pervasive demographic challenge across developed countries. While demographic transition theory anticipates convergence toward similar fertility regimes, cross-national heterogeneity remains poorly understood. This study investigates fertility trends, regional differences, and convergence dynamics among developed countries over the past decade. We conducted a comparative ecological time-series analysis using harmonized annual total fertility rate (TFR) data from the Human Fertility Database. 20 developed countries were grouped into five regions (Nordic, English-speaking, Western Europe, Southern Europe, and Eastern Europe). Ordinary least squares (OLS) models estimated annual fertility changes, with extended models controlling for GDP per capita (PPP) and female mean years of schooling. Between-region differences were assessed using ANOVA and Kruskal–Wallis tests, and convergence was evaluated by annual coefficients of variation (CV). Extended analyses incorporated 36 developed countries and 8 MENA nations to examine global consistency. Fertility declined across nearly all regions except Eastern Europe, which exhibited a modest rebound. The steepest reductions occurred in the Nordic (β ≈ −0.037) and English-speaking (β ≈ −0.029) regions, while Western and Southern Europe remained persistently low. Extended OLS models confirmed that these declines were structural rather than cyclical. The CV decreased markedly, indicating moderate convergence across developed countries, although Eastern Europe’s recovery introduced slight regional divergence in trend directions. During the COVID-19 period, fertility declined further in most regions but continued to a mild upward trend in Eastern Europe. Fertility levels across developed regions have gradually converged toward similarly low values, yet trend directions diverged, most regions continued to decline, while Eastern Europe rebounded modestly. This dual pattern reflects shared structural constraints alongside region-specific policy responses. Sustained demographic resilience will require coherent, long-term family policies that promote gender equality, work–family compatibility, and childcare affordability rather than short-term pronatalist measures.