Decreasing sperm quality: Findings from a 10 year gap longitudinal analysis of 2300 sperm samples from Brazil

Abstract

Objective: The objective of this study was to investigate if the seminal quality of men undergoing conventional semen analysis is deteriorating over the years. Methods: Retrospective longitudinal cohort study analyzing the sperm count, motility and morphology of 2300 semen samples, males undergoing conventional seminal analysis, from years 2000 to 2002 and 2010 to 2012, in an ART center in Brazil. Patients provided semen sample after 2-7 days of ejaculatory abstinence and analyses were performed according to the WHO recommendations. Periods were compared. Results: A total of 764 sperm samples were analyzed in 2000-2002 and 1536 in 2010-2012. In the past significantly higher mean sperm concentration/ml (61.7 ± 69.4 vs. 26.7 ± 27.3 × 106, p<0.001), total sperm concentration (183.0 ± 197.0 vs. 82.8 ± 89.5 × 106, p<0.001) and percentage of normal morphology (4.6% vs. 2.7%, p<0.001) were observed as compared to more recent years. The incidence of azoospermia was significantly lower in the past (4.9% vs. 8.5%, p=0.001) as well was the incidence of severe oligozoospermia (15.7% vs. 30.3%, p<0.001). In addition, 315 of 764 and 842 of 1536 men underwent ICSI in 2000-2002 and 2010-2012, respectively. There was no significant difference between the groups regarding the total fertilization rate (82.5% vs. 81.3%, p=0.619). Conclusion: The significant time-related decline in semen quality of infertile patients emphasizes the need for further studies addressing life-style. Since the fertilization potential through ICSI appears to remain steady there is enough reason for concern: the health and fertility of future generations are at risk. © Todos os direitos reservados a SBRA - Sociedade Brasileira de Reprodução Assistida.