Paternal Age May Also Affect ICSI Outcome in Oligozoospermic Patients

Paternal Age May Also Affect ICSI Outcome in Oligozoospermic Patients
May 15, 2009
Maternal age has been identified as a key determining factor in the success rates of IVF/ICSI procedures; however, relatively few studies have investigated the effect of advanced paternal age on ICSI outcome. Now, a recent retrospective observational study, published in the journal, Fertility and Sterility, suggests the negative effect of increased paternal age of oligozoospermic patients on implantation rate after ICSI. The study reports a 5% decrease in the chances of pregnancy for such couples with each year of increase in paternal age.

Renata Cristina Ferreira, from the Sapientiae Institute, Educational and Research Center in Assisted Reproduction, São Paulo, Brazil, and coworkers, analyzed the effect of age on ICSI outcome in both oligospermic and normospermic patients. The study subjects comprised of 1,024 couples treated with ICSI, using fresh spermatozoa. The results of linear logistic regression analyses demonstrated that paternal age in patients with abnormal sperm concentrations had a negative effect on the rates of implantation (regression coefficient value=−0.7009) and pregnancy [odds ratio (OR)=0.95]. However, no such effects on implantation (regression coefficient value=0.0566) and pregnancy rates (OR=1.00) were noted with normal sperm concentrations.

Contrary to the recent study findings, Aboulghar and coworkers (Reproductive Biomedicine Online, 2007) compared the ICSI treatment outcome in couples with male partners aged ≥50 years (mean age of 53±5 years) and younger age group male partners (mean age of 38.4±5.8 years). Although a higher fertilization rate was noted in the younger age group, pregnancy rate was not affected (37.9 versus 36.6%). Based on the study results, the researchers reported that paternal age may not affect the rate of pregnancy during ICSI. However, the study validated the need for further investigation to explore the long-term outcomes of such pregnancies.

Several previous studies have suggested the association of advanced paternal age with the increased risk for schizophrenia, certain cancers, birth defects, and neuropsychiatric conditions such as autism in the offspring. Plastira et al. (International Journal of Andrology, 2007) reported that paternal age may not be a factor that influences the incidence rate of aneuploidy in spermatozoa and ICSI outcome. The 25 oligoasthenozoospermia subjects involved in their study were divided based on their age into two groups: group A involved men aged between 20 and 34 years (n=10), and group B comprised of men 35-50 years of age (n=15). On data analysis of the three semen parameters (volume, concentration and progressive motility) the researchers did not find any statistically significant variation between the two groups. Using the dual and triple color fluorescence in situ hybridization, the researchers analyzed around 50,883 decondensed spermatozoa to determine the incidence of aneuploidy for chromosomes 13, 18, 21, X and Y, in the two groups.

In both the groups, the researchers noted a substantially higher incidence of disomy for chromosome 21, when compared to autosomal chromosomes, 13 and 18. In contrast to the older subjects (0.05%), the disomy rate of sex chromosomes was found to be significantly increased in the younger group (0.1%). The study results did not show a statistically significant variation in the mean number of clinical pregnancies and abortions between the two age groups. Also, the rates of aneuploidy for all the studied chromosomes were found to be similar both between and within the groups.

In the developed nations, there is a growing trend towards delaying parenthood till late thirties or older. An earlier study conducted in England and Wales reported an increase in the average paternal age from 29.2 years in 1980 to 32.1 in 2002. In view of enhanced prevalence of DNA damages in the sperm of older men, the Practice Committee of the American Society of Reproductive Medicine (ASRM) recommended the upper age limit of sperm donors to be less than 40.

Confirmation of the recent study results through larger studies may aid physicians in counseling patients regarding the detrimental effect of advanced paternal age on the success rates of ICSI.

References

1. Ferreira RC, Braga DP, Bonetti TC, Pasqualotto FF, Iaconelli A Jr, Borges E Jr. Negative influence of paternal age on clinical intracytoplasmic sperm injection cycle outcomes in oligozoospermic patients. Fertil Steril. 2009 Apr 29. [Epub ahead of print].

2. Aboulghar M, Mansour R, Al-Inany H, et al. Paternal age and outcome of intracytoplasmic sperm injection. Reprod Biomed Online. 2007 May;14(5):588-92.

3. Plastira K, Angelopoulou R, Mantas D, et al. The effects of age on the incidence of aneuploidy rates in spermatozoa of oligoasthenozoospermic patients and its relationship with ICSI outcome. Int J Androl. 2007 Apr;30(2):65-72.