Introduction
The birth rate of women aged 40 years or older has been rising steadily. Delaying childbearing is an ongoing and universal phenomenon. In Spain, the average age of women at childbirth remained at 32.2 years in 2019. In the last 10 years, the number of births to women aged 40 years and older has increased by 63.1%. In 2008, 4.2% of births were to women with maternal age  40 years, while in 2019, this percentage increased to 9.7%.1
Advanced maternal age has been historically defined as ≥35 years at the time of delivery and is widely associated with adverse obstetric outcomes. The risks of hypertensive disorders, gestational diabetes mellitus, placenta previa, placental abruption, and stillbirth are higher among women aged 35 years or older than among younger women.2-6
The incidence of stillbirth at 39–40 weeks of gestation is 2 in 1000 for women ≥ 40 years of age compared with 1 in 1000 for women < 35 years old. Women ≥ 40 years of age have a similar stillbirth risk at 39 weeks of gestation to younger women at 41 weeks of gestation.4 Induction of labour in older mothers is widely practiced as an intervention to reduce the risk of late stillbirth.5,6 A survey showed that 37% of obstetricians offer induction of labour at term to women aged 40–44 years and 55% to those ≥ 45 years.7 Studies suggest that there is a low threshold to perform a caesarean section in older women.5,6
Nonmedically indicated induction of labour compared with spontaneous labour is associated with an increased risk of caesarean delivery, especially in nulliparous women. However, spontaneous labour may not be an ideal comparison. Detailed data regarding the outcomes of nonmedically indicated induction of labour are still limited. As of 1 January 2015, the Gynaecology and Obstetrics service of the Álvaro Cunqueiro Hospital offered induction of labour to women aged ≥ 40 from the 39th week of gestation onwards. The objective of this study was to compare maternal and neonatal outcomes of nonmedically indicated induction of labour at term to those of expectant management in women over 40 years of age.