První světová válka a obyvatelstvo českých zemí

Approximately 100 thousand men of Czech origin died during the wartime operations in the years 1914 to 1918. The majority were aged between 23 and 35. The reproductive losses have been estimated at another 610 thousand (550 thousand children that were never born due to the absence of a man in the household and another 60 thousand civilian dead). In 1914 the population in the Czech territories numbered 10 million 283 thousand, in 1919 this number decreased to 9 million 921 thousand. The ratio of men to women decreased (in 1920 there were 92.5 men to every 100 women). This imbalance in age frequency, a result of the low birth rate, had a long term effect firstly on the number of marriages, then on the birth rate and eventually on the mortality rate. These long term effects were evidently still present at the close of the 20th Century.