There are five distinct demographic transition stages that are uniquely identified by birth and death rates. The first transition stage features high birth and death rates, causing a large fluctuation in population but with an overall small growth rate. The second stage sees a high birth rate paired with low death rates, which results in a rapid increase in total population.
The third demographic transition stage features both the birth and death rate falling, resulting in a slower growth of population. The fourth stage follows this trend but with the birth rate falling at a slightly faster rate compared to death rates. At the fifth stage of demographic transition, the death rate is higher than the birth rate, causing the total population number to begin dropping.
Various factors contribute to changing birth and death rates, including changing cultural preferences and improvements in medicine and technology. At the fourth stage, for example, personal lifestyle changes result in fewer married couples and couples who wait longer to have a child. This is in sharp contrast to the first stage where, due to high infant mortality, parents are more likely to have more children for added economical benefits and a higher chance of a child surviving to maturity.