Health inequalities start very early in life. By the time of school reception year (4-5 years of age), children from the most deprived areas of England are twice as likely to be obese as children from the most affluent areas. This illustrates the importance of the implementing policies to improve health at a very early stage, starting before conception, continuing through pregnancy, and then into infancy and childhood.
Source: NHS Digital http://digital.nhs.uk/catalogue/PUB30258