Many of the risk factors associated with pregnancy are more harmful when the expectant mother is over 35, according to a new study.
The study at the University of Eastern Finland found the risks associated with overweight, smoking, gestational diabetes and pre-eclampsia are higher in advanced maternal age than in younger expectant mothers.
Advanced maternal age refers to women giving birth at the age of over 35, researchers said.
Researcher Reeta Lamminpaa analysed nearly 700,000 expectant mothers and their newborn children by combining the data of 1997-2008 available from three national-level registers: the Finnish Medical Birth Register, the Finnish Hospital Discharge Register and the Finnish Register of Congenital Malformations.
The association between age and an additional risk factor on complications during pregnancy and the outcome of childbirth were studied in four risk groups: expectant mothers diagnosed with pre-eclampsia, expectant mothers who smoked, expectant mothers who were overweight and obese, and expectant mothers diagnosed with gestational diabetes.
The outcome of childbirth in advanced maternal age was compared to the outcome of younger mothers, ie those under 35.
In all of the four risk groups, the risks associated with pregnancy and childbirth were higher in advanced maternal age than in younger expectant mothers.
The age of over 35 as such was not a significant independent risk factor, but the risks increased when advanced maternal age was combined with an additional risk factor.
In expectant mothers over 35 and diagnosed with pre-eclampsia, pre-term birth and small-for-gestational-age infant were a particular risk.
In expectant mothers over 35 and who smoked, low birth weight, pre-term birth, foetal death and small-for-gestational-age infant were more likely than in younger expectant mothers.
Furthermore, in expectant mothers over 35 who were overweight or obese and diagnosed with gestational diabetes, pre-term birth, foetal death, large-for-gestational-age infant and pre-eclampsia in particular were more likely.
Moreover, overweight was associated with increased risk of Caesarean section in advanced maternal age.
The study showed that the above-mentioned four advanced maternal age groups clearly constitute a risk group that should be provided with enhanced guidance within maternity care, researchers said.
Early recognition of the risk groups would make it possible to guide mothers to further treatment at an earlier stage and, consequently, could help reduce the risks of the mother and the foetus alike, researchers said.
The findings are published in BMC Pregnancy and Childbirth, BMC Public Health, and Journal of Maternal-Fetal and Neonatal Medicine.
