Causes of male infertility: a 9-year prospective monocentre study on 1737 patients with reduced total sperm counts

• Published in: Human reproduction (Oxford) 2017-01, Vol.32 (1), p.18-31
• Main Authors: Punab, M., Poolamets, O., Paju, P., Vihljajev, V., Pomm, K., Ladva, R., Korrovits, P., Laan, M.
• Format: Article
• Language: English
• Subjects: Adult; Follicle Stimulating Hormone - blood; Humans; Infertility, Male - blood; Infertility, Male - etiology; Luteinizing Hormone - blood; Male; Middle Aged; Original; Prospective Studies; Semen Analysis; Severity of Illness Index; Sperm Count; Spermatogenesis - physiology; Spermatozoa; Testosterone - blood; Young Adult
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/dew284

STUDY QUESTION What are the primary causes of severe male factor infertility? SUMMARY ANSWER Although 40% of all patients showed primary causes of infertility, which could be subdivided into three groups based on the severity of their effect, ~75% of oligozoospermia cases remained idiopathic. WHAT IS KNOWN ALREADY There are few large-scale epidemiological studies analyzing the causes of male factor infertility. STUDY DESIGN, SIZE, DURATION A prospective clinical-epidemiological study was conducted at the Andrology Centre, Tartu University Hospital between 2005 and 2013, recruiting male partners of couples failing to conceive a child for over ≥12 months. Among 8518 patients, 1737 (20.4%) were diagnosed with severe male factor infertility. A reference group of fertile controls was comprised of 325 partners of pregnant women. PARTICIPANTS/MATERIALS, SETTING, METHODS The mean age of infertility patients and fertile controls was 33.2 ± 7.3 and 31.7 ± 6.3 years, respectively. All participants were examined using a standardized andrology workup, accompanied by a structured medical interview. Hormonal analysis included serum FSH, LH and testosterone. Semen quality was determined in accordance to the World Health Organization recommendations. Cases with spermatozoa concentrations of ≤5 million/ml were screened for chromosomal aberrations and Y-chromosomal microdeletions. MAIN RESULTS AND THE ROLE OF CHANCE The primary cause of infertility was defined for 695 of 1737 patients (~40%). The analyzed causal factors could be divided into absolute (secondary hypogonadism, genetic causes, seminal tract obstruction), severe (oncological diseases, severe sexual dysfunction) and plausible causal factors (congenital anomalies in uro-genital tract, acquired or secondary testicular damage). The latter were also detected for 11 (3.4%) men with proven fertility (diagnoses: unilateral cryptorchidism, testis cancer, orchitis, mumps orchitis). The causal factors behind the most severe forms of impaired spermatogenesis were relatively well understood; causes were assigned: for aspermia in 46/46 cases (100%), for azoospermia in 321/388 cases (82.7%), and for cryptozoospermia in 54/130 cases (41.5%). In contrast, 75% of oligozoospermia cases remained unexplained. The main cause of aspermia was severe sexual dysfunction (71.7% of aspermia patients). Azoospermia patients accounted for 86.4% of all cases diagnosed with secondary hypogonadism and 97.1% of patients with seminal tract obstruc