Migrant births increase by 65%
Pregnant woman
More foreign women of child-bearing age have come to the UK
The number of births in the UK to women born overseas rose by 65% between 2001 and 2007, official figures show.
The Office for National Statistics's quarterly population report showed that over the same period, births to UK-born women increased by only 6.4%.
That meant that by 2007 more than one in five children born in Britain had a foreign-born mother, the ONS said.
It noted higher fertility rates among foreign-born women, compared to women born in the UK.
During the six-year period analysed, the number of births to British-born women increased by 6.4%.
This rise was attributed to higher fertility rates - defined as the number of live births per 1,000 of the population.
But there was a different reason for the larger increase in births to foreign-born mothers - a rise of 14% in the absolute number of women of child-bearing age from overseas living in the UK.
Women's own socio-economic characteristics, including economic activity and social class, are significantly associated with childlessness
Office for National Statistics report
The ONS said the rise was due to the increase in the population of younger women born outside the UK, particularly at ages where fertility is highest.
It also noted higher fertility levels displayed by foreign-born women in the UK compared with their UK-born counterparts."
Career choices
In a separate study, the ONS found that married women were more likely to become mothers than women who cohabit with their partners
It published the results of a study of lifelong childlessness, which followed more than 12,700 women born between 1956 and 1960.
By their early 40s, about 17% of women were childless, in part corresponding with their relationship status.
"The data shows that lack of a co-resident partner still appears to be one of the main factors associated with childlessness," the study said.
However, career choice was also linked to childlessness, with more women employed in professional, managerial or technical occupations who did not have children.
In 2001, about 30% of mothers were in these occupations, compared with about 42% of childless women.
"Irrespective of their partnership status, women's own socio-economic characteristics, including economic activity and social class, are significantly associated with childlessness," the report said.
