By ALICE CACHIA N

EARLY women having children - twice as many as 25 years ago.

A woman’s childbearing age is assumed to start when she is 15 and ends the day before her 46th birthday, according to the Office for National Statistics.

All women born in 1971 will turn 46 by the end of the year - and 18% of those won’t have given birth to any children. That compares to just 9% who were born in 1946. Women who were born in 1946 are actually the most likely since records began to have had at least one child. Since then the number has been generally falling although it has actually crept up since 1961. Some 20% of women born that year never had a child. Of women born in 1971, 34% had a first child by the age of 25 and more than half had given birth by the age of 30.

Nearly three quarters had at least one child by the time they were 35 and more than 80% by the age of 40.

Figures show that nearly four in every ten women born in 1971 have given birth to two children in their lifetime, while 18% have an only child, 17% have three children, and one in 10 has four or more kids.

The data also shows that women are leaving it longer to have children.

Among women who were born in 1992 - and will therefore turn 25 by the end of this year - a quarter of them have given birth to their first child.

Among those born just 10 years earlier, nearly a third had given birth by that age, while for those born 50 years earlier, six in ten had.

Teenage pregnancy rates are also falling.

Among women born in 1981, 18% were aged between 16 and 19 when they first gave birth to a child.

The number began to steadily drop, and 14% of women born four years later in 1985 gave birth while they were teenagers. This rate remained the same until 1987 when it decreased even further. Those born in 1998 will turn 20 in 2018, and just 7% have given birth as a teenager. Women born between 1952 and 1955 had the highest teenage pregnancy rates, with 23% giving birth between 16 and 19.