Already around 1750 the illegitimacy ratio was slightly higher in the countryside of Eastern Sweden than that of Western Sweden. The differences between the two regions started to grow around the turn of the century (1800). The slight increase in illegitimacy in Western Sweden was mostly due to the growing number of unmarried young men and women in the population, whereas in Eastern Sweden it became more and more common that women gave birth to their first child without being legally married.

According to the marriage section of the Law of 1734 there was just one way of getting lawfully wedded. The law declared that the marriage act (vigseln) should constitute the marriage. But people in both regions lived in accordance with the popular norm which allowed future married couples to start their matrimonial life before the wedding. So, during the investigated period it became more and more common that couples just used the marriage act to legalize their relationship when they already were expecting their first child.

The concentration of land and capital to a fewer number of owners which occurred in Eastern Sweden, also brought about a growing landless proletariat for whom in had become possible to marry without any access to land. The uncertain economic situation of the landless young people caused interrupted marriage plans and illegitimate births. In Western Sweden the development was characterized by decentralisation and by the division of big holdings. Marriages could not be decided upon until the economic basis for the new households had been created. Once this problem was solved the matrimonial life could start. Pregnant brides were the result, but seldom illegitimate births.