Pregnancy outcome in mothers over the age of 35

The proportion of pregnancies occurring in women of at least 35 years of age has increased from 6.2% in 1980 to 22.3% of births in 2016. This review summarizes recent epidemiological and basic scientific studies investigating the association between older maternal age and adverse pregnancy outcome(s), and clinical studies which investigate the effects of intervention to reduce adverse events.

Women of at least 35 years of age have increased risk of maternal and foetal complications in pregnancy including: stillbirth, a small for gestational age baby, preterm birth, preeclampsia and maternal death. These risks increase with increasing age. The reasons for this increased risk are incompletely understood, but likely involve ageing of the maternal cardiovascular and endocrine systems which impacts upon placental function. Intervention, by induction of labour (IOL) at 39-week gestation does not increase operative deliveries or short-term adverse maternal and neonatal outcomes and would reduce perinatal mortality.

The additional risks of pregnancy should be discussed with women of at least 35 years of age; additional foetal surveillance may be required in the antenatal period. The benefits and risks of IOL at 39-week gestation should be discussed with women at least 35 years of age.