Evaluation of Reproductive Parameters in Men with Solitary Testis

We evaluated reproductive parameters of men with a solitary testis compared to men with bilateral testes.

We conducted a cross-sectional case-control study comparing infertility evaluation parameters in men with a solitary testis to men with 2 testes. Men presenting for fertility consultation with semen analysis data collected within 90 days of clinical and hormonal assessment were included. Differences in semen and hormonal levels were characterized using descriptive statistics, multivariate analysis on matched semen parameters and evaluation of hypogonadism subtypes.

A total of 837 men were identified. After applying exclusion criteria, we analyzed 29/39 men (74%) with a solitary testis and compared them to 656/798 men (82%) with 2 testes. A 1:1 match on sperm concentration and motility showed follicle-stimulating hormone was more elevated in men with a solitary testis (median 13.9 mIU/ml, IQR 5.8-24.2) than in men with bilateral testes (5.0, 3.4-9.8, p=0.009). Men with bilateral testes were uniformly azoospermic after a follicle-stimulating hormone level of 25.0 mIU/ml, whereas men with a solitary testis had some sperm in the ejaculate at follicle-stimulating hormone levels as high as 54.6 mIU/ml. Testosterone levels were similar between men with a solitary testis (median 381 ng/dl, IQR 248-500) and 2 testes (387, 296-507). The prevalence of compensated hypogonadism (high luteinizing hormone and normal testosterone) was higher in men with a solitary testis (8/29, 28%) than in men with bilateral testes (54/656, 8.2%, p=0.002).

Men with a solitary testis have compensated pituitary strain as indicated by higher serum follicle-stimulating hormone and luteinizing hormone levels for the same testosterone and semen parameters compared to men with bilateral testes. Followup is needed to evaluate any detrimental consequences of this compensated state that may lead to pituitary burnout and decreased testicular function.