Postponing pregnancy reduces the total number of children and increases inequalities in maternal risk factors.
In Finland, the proportion of births among women aged over 35 has increased, in 2024 accounting for 27.7% of all births. This trend has important implications both at the societal level and for individuals.
"If there is one thing women considering having children later in life should keep in mind, it is that postponing childbirth is not without risks. For some women, particularly those from lower socioeconomic backgrounds, these risks are even greater", says Doctoral Researcher Zahra Roustaei.
Zahra Roustaei's doctoral resear chexamined how maternal age and socioeconomic status together influence the total number of children and maternal health risk factors.
The findings showed that postponing the first birth until after the age of 30 was linked to a total fertility rate of fewer than two children per woman. The same pattern was observed across all socioeconomic groups, but women with low socioeconomic status had the lowest completed fertility rates in most age groups. For population growth to be sustained, the number of children per woman should remain above the replacement-level fertility of 2.1.
Maternal health inequalities grow with increasing age
Older women face higher rates of obesity and gestational diabetes, which are known to increase the risk of complications during pregnancy. These maternal health risk factors are more common among women with lower socioeconomic status, and the trend toward later pregnancies widens these inequalities.
For example, among women aged 35 years or older, those who were long-term unemployed had up to 2.3 times higher risk for maternal obesity and 1.6 times higher risk for gestational diabetes than women in upper-level occupations of the same age. This may be linked to long-term socioeconomic disadvantage, which can increase older mothers' vulnerability to poor maternal health.
It was estimated that 29 151 cases of maternal obesity (2004-2015) and 9 045 cases of gestational diabetes (2008-2015) could have been prevented if the differences between population subgroups had been eliminated.
In addition, the risk of perinatal depression is highest among teenage mothers. However, among women with lower socioeconomic status who postpone childbirth, the risk rises again for those aged 35 and older. These findings raise an important question for decision-makers: What should be the priorities of public health and social policy in a welfare state?
There is no single-pronged solution
Addressing very low fertility rates and maternal health disparities is a complex task. At the ecosystem level, it requires actions that target ecosocial forces and social determinants contributing to the postponement of childbirth and the development of maternal risk factors. At the same time, low socioeconomic status should be recognized as a risk factor in individual-level interventions, particularly among women who postpone pregnancy.
The research was based on data from the Finnish Medical Birth Register, the Finnish Hospital Discharge Register, and Statistics Finland. The data covered the years 1987 to 2016 and included as many as 1,792,792 women who gave birth in Finland.
