Effects of ejaculatory frequency and season on variations in semen quality.
OBJECTIVE
To describe the intraindividual variation in semen parameters.


METHODS
Prospective, longitudinal study.


METHODS
Academic research environment.


METHODS
Twenty-seven healthy men, followed monthly for 16 months.


METHODS
Monthly semen samples were collected, as well as information regarding duration of abstinence, febrile episodes, and ejaculatory frequency.


METHODS
Sperm concentration, percentage immotile spermatozoa, and percentage morphologically normal spermatozoa.


RESULTS
There were no significant seasonal variations in sperm concentration, motility, or morphology. The ejaculatory frequency was significantly higher during spring compared with winter months. There was a significant difference in sperm concentration with respect to having one, two, or more than two ejaculations during a 7-day period before the abstinence period. Sperm motility and morphology were not affected by ejaculatory frequency. Duration of abstinence, ejaculatory frequency, and fever accounted only little for the high intraindividual variation in individual semen parameters. Three semen samples compared with two reduced the intraindividual variations as follows: sperm concentration from 41% to 33.5%, percentage normal spermatozoa from 6.9% to 5.7%, and percentage immotile spermatozoa from 19% to 15.5%.


CONCLUSIONS
Ejaculatory frequency but not season significantly affected sperm concentration. Most of the intraindividual variations in semen parameters could not be explained by duration of abstinence, fever, or ejaculatory frequency.
University Department of Growth and Reproduction, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. ecarlsen@rh.dk
Elisabeth
E
Carlsen
Jørgen Holm
JH
Petersen
Anna-Maria
AM
Andersson
Niels E
NE
Skakkebaek
D004542:Ejaculation / Q000502:physiology; D005298:Fertility / Q000502:physiology*; D005334:Fever; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010808:Physical Examination; D012016:Reference Values; D012621:Seasons; D012661:Semen / Q000502:physiology*; D012746:Sexual Abstinence / Q000502:physiology; D013076:Sperm Count; D013997:Time Factors