New ways of calculating older mothers’ personal risk of serious pregnancy problems have been developed following a UK study.
The Manchester Advanced Maternal Age Study (MAMAS) found levels of placental growth factor and antioxidant capacity could help to predict pregnancy risks in women aged 35 and over.
A team from Tommy’s Stillbirth Research Centre at The University of Manchester and St Mary’s Hospital, part of Manchester University NHS Foundation Trust, collected data from 527 mothers across six UK hospitals between March 2012 and October 2014. Of these, 158 were in their 20s, 212 in their 30s, and 157 in their 40s.
The researchers compared demographic and medical data with blood samples taken at 28 and 36 weeks of pregnancy and matched samples from older and younger mothers with similar characteristics to look for any impact of their age.
They also compared samples from older mothers with different pregnancy outcomes, including stillbirth, premature birth, babies admitted to neonatal intensive care, and babies born very small or with low Apgar scores.
Placental growth factor was found to have 74% accuracy for predicting a negative pregnancy outcome, while antioxidant capacity was accurate 69% of the time, they write in BMC Pregnancy Childbirth.
The researchers found previous successful pregnancies protected against future problems, with mothers who had given birth to a live baby before having about half the risk of adverse pregnancy outcomes compared to women in their first pregnancies.
Women over 35 who smoked had a four-fold increased risk of adverse pregnancy outcomes, while this dropped to two-fold for ex-smokers.
Promising avenue
Lead author Professor Alex Heazell, professor of obstetrics at The University of Manchester, said: “Mothers aged 35 years or over are increasingly common in many countries, and unfortunately having a baby later in life has long been associated with higher pregnancy risks.
“We already know the changes in oxidative stress and inflammation we saw in this study are associated with many pregnancy complications – but for the first time here, we found they were also present in older mothers, which could be damaging the placenta and might explain why older mothers face these higher risks.
“If we measure these biomarkers in the placenta, along with demographic information and clinical variables that we already know affect pregnancy risk, that could give us a better way of predicting someone’s individual risk of an adverse pregnancy outcome at an older age.
“However, larger studies are required to see if these markers can be developed into an individual predictive model.”
Jane Brewin, chief executive of Tommy’s charity, which funded the research, added: “This promising new avenue of research has really exciting potential for clinical practice; it could predict older mums’ pregnancy outcomes as early as 28 weeks, so doctors can act to prevent problems for the most vulnerable and avoid unnecessary medical treatment for those with lower risks.”
Lean SC, Jones RL, Roberts SA et al. A Prospective Cohort Study providing Insights for Markers of Adverse Pregnancy Outcome in Women of Advanced Maternal Age. BMC Pregnancy Childbirth. October 2021. DOI: 10.1186/s12884-021-04178-6
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