1. Improvements in housing; cleaner drinking water; food and drink laws; improved sewerage; Clean Air Acts.
  2. Changes in the position of women; decline in the infant mortality rate; children are now an economic liability; child-centred families.
  3. Class differences in factors such as family size, access to good housing, sanitation, nutrition, mother’s knowledge of hygiene, access to health services, uptake of immunisation.
  4. Married women working may lead to a fall in the birth rate because they tend to delay childbearing or may not have children at all
  5. Smaller families; better knowledge of hygiene; improved ante- and post-natal services; better nutrition.
  6. They are continuing their education; starting careers; cohabiting and establishing a home before starting a family.
  7. Immigrant mothers tend to have higher fertility rates.
  8. Migrants tend to be of working age and in the short term this will reduce the dependency ratio. However, because migrants tend to be young and therefore fertile, they are more likely to produce children and this will increase the dependency ratio.