Over the last decade, delayed childbearing has become a trend in developed countries. It is proven that advanced maternal age plays a dominant role in determining the success of in vitro fertilisation (IVF) treatments.1 However, the impact of advanced paternal age on IVF outcomes is still poorly known. Recent studies found that a man’s age can affect testicular functions and sperm parameters.2,3 Paternal ageing was also found to be associated with increased incidence of DNA damage, chromosomal aberrations, and embryonic aneuploidy.4 These can lead to decreased fertilisation and blastulation rate or increased miscarriage rate and thus a decreased live birth rate.3,5,6 The following was investigated in this study: how does advanced paternal age affect sperm parameters and the outcome of intracytoplasmic sperm injection (ICSI) cycles.
Data were collected retrospectively on all couples with a female age <35 years at the authors’ private fertility clinic between January 2013 and December 2018. A total of 135 fresh embryo transfer cycles were analysed; two groups were formed based on the paternal age: <40 years group and ≥40 years group. Evaluation of all semen parameters was done according to World Health Organization (WHO) standard criteria (2010).7 All embryos were fertilised by ICSI using fresh, frozen, or testicular sperm extraction sample. In the <40 years group (average age 34.00±3.79), 101 fresh blastocyst transfers were carried out, while in the ≥40 years group (average age 43.18±2.47), 34 blastocyst transfers were carried out. Cycles with pre-implantation genetic testing were excluded from the analysis. The measured IVF outcomes were fertilisation rate, blastulation rate, implantation rate, clinical pregnancy rate, and miscarriage rate.
The mean maternal age did not differ between the two examined groups (31.43±3.32 in the <40 years group and 31.76±4.29 in the ≥40 years group). The mean initial sperm count was significantly higher in the <40 years group than in the ≥40 years group (58.87 million/mL versus 44.38 million/mL, p=0.0464), and sperm motility was also significantly higher in the <40 years group (49.98% versus 37.18%, p=0.0054). The fertilisation rate was slightly higher in the <40 years group (70.11%) but not significantly different from the ≥40 years group (66.67%, p=0.4371). However, the authors found a significantly higher blastulation rate in the <40 years group compared to the ≥40 years group (60.87% versus 56.18%, respectively, p=0.02). The implantation rate (41.22% [54/131] versus 52.17% [24/46], p=0.1689) and clinical pregnancy rate (42.57% [43/101] versus 61.76% [21/34], p=0.0734) did not differ significantly in the examined groups after IVF-ICSI. Additionally, no significant difference in case of miscarriage rates (22.22% [12/54] in <40 years group versus 16.66% [4/24] in ≥40 years group, p=0.7634) was found.
Based on these results, the quality of sperm seems to decline with age, which demonstrates that male fertility also has a defined lifetime. However, IVF-ICSI can compensate for this. With the studies findings, the authors would like to draw men’s attention to the increasing health risks associated with late childbearing.