Women in the south of England are giving birth ten years later on average than those in the north, figures have revealed.
The Office for National Statistics study showed a huge gap in the age at which women are most likely to have children.
A new mother in the perceived to be more affluent south of England is likely to be in her 30s, while women in the north will normally have a baby in their 20s.
They are most likely to give birth between the ages of 25 and 29, compared to 30 and 34 for their southern counterparts.
The ONS indicated the divide was down to varying earnings and differences in quality of education.
Other factors included the cost of childcare and longer working hours.
Many parents are paying up to £20,000 a year on childcare in London, where longer working hours also persuade many women to have children later in life.
The figures are vastly different to those in 1986, when almost all regions saw their highest fertility between the ages of 25 to 29.
By 2006, fertility was highest between age 30 and 34 in 45% of the country.