Introduction
Over the past few decades, there has been an increase in the average age of women becoming pregnant with their first and subsequent pregnancies observed in developed countries, including Poland. According to the data presented by Eurostat in Poland, the highest fertility of women in the age group of 20-24 years moved in 1995 to the group of 25-29 years in 2015. The median age of all women giving birth increased from 26.9 years in 2005 to 29.2 in 2015 and women giving birth to the first child from 23.7 years in 2005 to 27 in 2015. A similar tendency occurs in many European countries, as illustrated in Figure 1. The reason for this phenomenon is very complex. It consists of social, cultural, economic and demographic factors [1]. People postpone reproduction to a later stage of life to pursue educational goals, professional development and financial stabilization [2-5]. Many women admit that the lack of a suitable partner is the main reason for late motherhood [6, 7].
According to current data, advanced maternal age is associated with an increased risk of some of the complications of pregnancy and childbirth [8-11]. Most frequently, these complications are associated with comorbidities, the incidence of which also increases with age. However, despite numerous studies on the subject since the 80s of the last century, maternal age has not been validated as an independent risk factor for adverse pregnancy outcomes [12-16]. The available literature mainly concerns Western European, Asian, Australian and North American populations. There is a lack of studies examining Central European, including Polish, population. As a result of different socioeconomic factors and ethnic structure as well as different healthcare policies, it could be possible that there are differences in the influence of maternal age on the incidence of peripartum complications.