The number of 25-year-old women having had a child is at a record-low, with only a quarter of women reaching the threshold having had at least one child, new figures find.
The Office of National Statistics also found that 18% of women who were aged 45 in 2017 were childless at the end of their childbearing years compared to 10% a generation before.
The most common age of childbirth for women who had reached age 45 years in 2017 was 31 years, compared to between 23 and 24 years for women born the generation before in 1945, the ONS found.
There also a record-low in the average “completed” family size for 45-year-old women in England and Wales in 2017, which was 1.89 children.
Paula Guy, the Statistician of the report described the figures as show women "delaying their childbearing until their 30s".
“Looking at women who reached the age of 45 in 2017, we can see that they had smaller families than earlier generations, with an average completed family size of 1.89 children," she said.
“Two children remains the most common completed family size for women born in 1972. However, the proportion of women with two children was lower, while the proportion of women with one child or no children was greater, than for women born a generation before, in 1945.
“There are signs that women who are still in their childbearing years are showing similar patterns of delaying their childbearing until their 30s and having fewer children overall."
The ONS describe a woman’s childbearing as being assumed to start at age 15 years and end at the age of 45 years (the day before her 46th birthday).