Document Type

Working Paper

Publication Date



By the late 1990s fertility in the developed world had declined to 1.6 births per woman, a level substantially lower than projected in the 1980s. This study examines recent trends and patterns in fertility in the developed world with particular emphasis on the effects and implications of changes in the timing of childbearing. The main objective is to demonstrate that while fertility in these countries is indeed low, women’s childbearing levels are not as low as period measures such as the total fertility rate suggest. To obtain a full understanding of the various dimensions of fertility change, several indicators are examined, including period and cohort fertility by birth order and childbearing preferences. An analysis of these indicators demonstrates that period fertility measures in many developed countries are temporarily depressed by a rise in the mean age at childbearing. The distortion of the TFR is as great as 0.4 birth per woman in Italy and Spain. These effects have been present in many developed countries since the 1970s and could continue for years into the future. But tempo effects are temporary in nature and once the postponement of childbearing ends-as it eventually must-the corresponding fertility-depressing effect stops, thus putting upward pressure on period fertility. Countries with very low fertility and substantial tempo effects may well experience modest rises in fertility in the near future if the timing of childbearing stabilizes. Even if this happens, however, it seems highly unlikely that fertility will rebound to the replacement level.