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.