Edwards syndrome (trisomy 18) occurs in 1: 8000 live births and is closely 
related to the mother's age. Most of the embryos and fetuses with trisomy of 18 
chromosome pair undergo natural abortion. Change in number and structure of 
chromosomes usually takes place spontaneously. However, the incidence of 
chromosome mutations increases with the presence of mutagenic factors. One of 
the chemical mutagenic factors is benzopyrene - present in cigarette smoke. 
Prenatal cytogenetic diagnostic is used for detecting diseases and clinical 
syndromes conditioned by chromosome aberrations. To this date the "golden 
standard" of this diagnostic is the assessment of the fetus karyotype by means 
of analysis of chromosome banding pattern from amniotic fluid-derived cells. The 
aim of the study was the analysis of indications for genetic amniocenteses 
carried out in the last 5 years and in case of which trisomy of chromosome 18 
(Edwards syndrome) was diagnosed. The analysis covered 1593 results of fetus 
karyotypes obtained from Cytogenetic Laboratory of the Central 
Gynecological-Obstetric Clinical Hospital in Poznań over the last 5 years. The 
study procedure consisted in producing cell culture from amniotic fluid, 
appliance of appropriate color techniques and thorough microscopic analysis of 
chromosome banding pattern. As a result of the analysis it was discovered that 
in 1538 cases the karyotype was normal, and in 55 cases trisomy 18 was 
diagnosed, which constituted 3% of all cytogenetic tests. The highest number of 
trisomy 18 cases was noted in 2009 - 19 cases, which constitutes 5% of all 
tests. In 2010 and 2011 the results included respectively 2% and 3% of diagnosed 
trisomy 18 (Edwards syndrome). In the last 5 years normal results for karyotypes 
constituted 87%, in 10% cases other aberrations were diagnosed through 
cystogenetic tests, whereas 3% of the results have shown trisomy 18 (Edwards 
syndrome The most frequent indications for performing genetic amniocentesis, as 
a result of which trisomy 18 was diagnosed, were defects in ultrasound image, 
including fetal hydrops which constituted 27.3% of all indications. Malformation 
syndrome in fetus and hydramnion constituted only 9.1% of indications for 
cytogenetic tests where trisomy 18 was diagnosed. The highest incidence rate of 
trisomy 18 was diagnosed in fetuses of women aged between 30 and 34. These were 
followed by 29 fetuses with Edwards syndrome in mothers aged between 25 and 29.