Seasonality of Births in the Netherlands: A Decomposition of Recent Trends

Karen Haandrikman, University of Groningen

Explaining seasonal patterns of births continues to be a challenge to demographers. Different patterns have been found across and within countries. Little research on seasonality has been done for the Netherlands. We examine seasonal fluctuations in fertility in the twentieth century in the Netherlands. A decomposition into parity and marital status is conducted, to explain the observed patterns. Since the 1970s, when the majority of women started to use modern contraceptives, the seasonal pattern of births has changed. This raises the question whether volitional human control is a key determinant in explaining seasonality. The data comes from the Dutch population register, and covers the period 1995-2001. The Dutch pattern takes a middle position between northern and southern Europe, with a peak in births in August and September. First births and marital births determine the general seasonal pattern of births. Second births are less planned, while non-marital births are more planned.