Temporal trends in human semen parameters in New England in the United States, 1989-2000.

The current study explores trends in semen parameters in New England in the United States. A retrospective review was performed of 551 semen analysis records from 1989 to 2000 at Vincent Memorial Andrology Laboratory of Massachusetts General Hospital. After age adjustment, semen pH and motility significantly increased 0.05 units/year and 2.33%/year, respectively, while sperm with normal morphology decreased 0.33%/year. Sperm concentration showed a small upward trend. The year of birth in the present study ranged from 1932 to 1981; 2% were born between 1932 and 1941, 13% between 1942 and 1951, 48% between 1952 and 1961, 36% between 1962 and 1971, and 1% were born between 1972 and 1981. There were significant positive relationships between year of birth and semen volume (0.04 mL/1-year interval increase in year of birth) and motility (0.61 percent/1-year interval increase in year of birth), as well as with sperm concentration and morphology. Overall, there were temporal and year of birth trends in several human semen parameters.