Trends of the Delay and Variance of Childbirth Timing by Completed Number of Children

The timing of childbirth has undergone significant changes in the past decades. However, it may not be feasible for individuals with many children to further delay the timing of each childbirth given the biological constraints on fecundability and social age deadline for childbirth. Thus, the delay in having children and the increasing heterogeneity in its timing may present different trends when analyzed retrospectively by completed number of children. This study investigates the age at childbirth by birth order among women age 40+ in 17 European countries and Canada based on the number of children they have. Our findings show that individuals having more children tend to have each child at earlier ages, with less variation in timing, compared to the counterparts with fewer children. This suggests that changes in the timing of childbirth are more pronounced among individuals having fewer children and less so among those with having more children.