Body mass index (BMI) has been demonstrated to affect female fertility; however, little information is available on the impact of BMI on male fertility or semen parameters. Therefore, the study objective was to determine the relationship between BMI and semen parameters, including sperm chromatin integrity. We analyzed data on semen samples from 520 men who were grouped based upon calculated BMI values (normal, 20-24 kg/m(2); overweight, 25-30 kg/m(2); obese, >30 kg/m(2)). The data collected included patient height and weight, semen volume, sperm concentration, percent sperm motility, percent sperm morphology (normal forms), and sperm chromatin integrity (DNA fragmentation index [DFI]). Data were analyzed by regression analysis and analysis of variance (ANOVA) with Tukey's test for multiple pairwise comparisons. The overall BMI mean (+/-SEM) was 27.5 (+/-0.49) kg/m(2). Linear regression revealed a significant (P < .05) and negative relationship between BMI and the total number of normal-motile sperm cells. ANOVA revealed a significant difference (P < .05) in the total number of normal-motile sperm cells among the different BMI groups. The number of normal-motile sperm cells per BMI group was as follows: normal, 18.6 x 10(6); overweight, 3.6 x 10(6); and obese, (0.7) x 10(6). All multiple pairwise comparisons were found to be significantly (P < .05) different. The overall DFI mean (+/-SEM) was 24.7 (+/-2.57). Linear regression revealed a significant (P < .05) and positive relation between BMI and DFI. Men presenting with a BMI greater than 25 kg/m(2) have fewer chromatin-intact normal-motile sperm cells per ejaculate. Therefore, to ensure maximum fertility potential, patients may be advised to reduce body weight.

https://onlinelibrary.wiley.com/doi/pdf/10.2164/jandrol.05124

Impact of body mass index values on sperm quantity and quality.

Previous studies have indicated that sperm quality may be related to unexplained recurrent pregnancy loss. This study evaluated the degree of sperm DNA fragmentation using the TUNEL assay on sperm from 24 couples with unexplained recurrent pregnancy loss (RPL) compared to sperm from 2 control groups: donors of known fertility and unscreened men from the general population. The percentage of sperm staining positive for DNA fragmentation was increased (p < .001) in the RPL group (38 +/- 4.2) compared to the donor (11.9 +/- 1.0) or general population (22 +/- 2.0) control groups. In the RPL group, no correlation was observed between semen quality parameters and the TUNEL data. These data indicate that some RPL patients have a significant increase of sperm DNA fragmentation, which may be causative of pregnancy loss in some patients.

https://www.tandfonline.com/doi/pdf/10.1080/01485010290099390

Sperm DNA fragmentation is increased in couples with unexplained recurrent pregnancy loss.

The results of several studies point to an increased likelihood of abnormal semen parameters among overweight men, and an elevated risk for subfertility among couples in which the male partner is obese. Obesity is, therefore, associated with a higher incidence of male factor infertility. Several mechanisms might account for the effect of obesity on male infertility, both directly and indirectly, by inducing sleep apnea, alterations in hormonal profiles (reduced inhibin B and androgen levels accompanied by elevated estrogen levels) and increased scrotal temperatures, ultimately manifesting as impaired semen parameters (decreased total sperm count, concentration and motility; increased DNA fragmentation index). Neither the reversibility of obesity-associated male infertility with weight loss nor effective therapeutic interventions have been studied in-depth. The increasing prevalence of obesity calls for greater clinical awareness of its effects on fertility, better understanding of underlying mechanisms, and exploration into avenues of treatment.

https://www.clevelandclinic.org/reproductiveresearchcenter/docs/scipubs2009_01.pdf

The effect of obesity on sperm disorders and male infertility.

Spermatozoa selection at high magnification before intracytoplasmic sperm injection seems to be positively associated with pregnancy rates after day 3 embryo transfers. The aim was to demonstrate an association between the presence of vacuoles in sperm nuclei and the competence of embryos to develop to day 5. Grading of spermatozoa at x 6000-x 12,500 magnification: grade I, no vacuoles; grade II, or=1 large vacuole; grade IV, large vacuoles with other abnormalities. The outcome of embryo development in a group of 25 patients after sibling oocyte injection with the four different grades of spermatozoa showed no significant difference in embryo quality up to day 3. However, the occurrence of blastocyst formation was 56.3 and 61.4% with grade I and II spermatozoa respectively, compared with 5.1% with grade III and 0% with grade IV respectively (P < 0.001). Spermatozoa selection at high magnification using Nomarski interference contrast is useful to identify more precisely the size and the number of nuclear vacuoles that greatly exert a negative effect on embryo development to the blastocyst stage. These observations confirm previous studies pointing to possible 'early and late paternal effects', both of which may have an impact on early embryonic development.

https://www.rbmojournal.com/article/S1472-6483(10)60308-2/pdf

Blastocyst development after sperm selection at high magnification is associated with size and number of nuclear vacuoles.

Elevated sperm chromosome aneuploidy and apoptosis in patients with unexplained recurrent pregnancy loss.

A study was carried out to determine whether males contribute to repeated early pregnancy loss. Semen samples were analyzed from proven-fertile men (n = 51 group I) and from men whose partners presented with early pregnancy loss (>3 first trimester abortions, n = 32 group II). Routine analysis, sperm function tests, and ultrastructural studies of sperms were carried out. Female factor could be identified in 25 (78%) couples, and in 7 (22%) no cause either male or female could be identified and the semen analysis was normal. Percent morphologically normal did not differ significantly between the groups, but increased sperm head abnormalities were seen. The functional tests were all normal except for a significant decrease in the capacity of nuclear chromatin to decondense in vitro. The ultrastructural studies showed defects of chromatin condensation and irregular nuclei with vacuoles. This study points to the loss of chromatin integrity as a possible contributing factor from males to early pregnancy loss.

P K Meherji

Papers

Poor quality of sperm as it affects repeated early pregnancy loss.