Birth and death rates are high and the death rate fluctuates from year to year. The Early Expanding Stage . Fertility remains high, but improved conditions mean falling death rates. Population therefore increases. The Late Expanding Stage .
Death rates are low and fertility is declining but population is still increasing.
The Low Stationary Stage . Birth and death rates are low and the birth rate fluctuates. Some writers suggest that there is a fifth stage where birth rates fall below death rates so population levels fall. The reasons for falling death rates are improved conditions and health care. The reasons for falling fertility are less clear.