Background: The Central Statistical Offices in Europe indicate an increase of women's parity age and extramarital births.
Objectives: The aim of this study was to analyze the chosen demographics of parity in European countries of Poland, Spain, England and Wales in 1996-2011.
Material and methods: Statistical packet: women's average age at the time of their first and subsequent births, newborns' average body weight in relation to the age of mother; live marital and extramarital births. The age of mothers giving birth to their first and subsequent children in 1998-2011 in all of the researched countries is presented, and next compared in 1999, 2005 and 2011. An analysis of the births of children in marital and extramarital relationships as well as the body weight of live newborns is presented in detail in 1996-2006, and next in 6 year periods: 1999, 2005 and 2011.
Results: The average age of the mother giving birth to her first baby in 1996-2011 oscillates around: 26-27 years in England and Wales, 28-30 years in Spain and 23-26 years in Poland. In Poland, the highest average children's body weight, 3394 g, was achieved by children born by mothers at the age of 25-29. In Spain, however, at the mothers' age of 20-24, it was 3317 g. In England and Wales, at 30-34 years, it was 3262 g. The number of extramarital births in comparison to marital births is increasing. England and Wales has the lowest percentage of marital births, whereas Poland, the highest. In Spain, England and Wales we can observe an increase of extramarital births, while in Poland this number is stable at around 21.3%.
Conclusions: The age of women having their first baby, the parity of later children, and extramarital births are increasing. In Poland, infant body weight is significantly bigger than in Spain, England and Wales.
Keywords: birth intervals; fertility; parity.