NEW YORK (Reuters Health) - The results of a new study suggest that prolonged sexual abstinence may actually reduce, rather than increase, semen quality in oligozoospermic men.

"After only 2 days of abstinence, sperm from patients with male factor infertility initiate a process of quality degradation," Dr. Eliahu Levitas of Soroka University Medical Center in Beer-Sheva, Israel and colleagues write in the June issue of Fertility and Sterility.

Dr. Levitas and his team note that most clinics likely follow World Health Organization recommendations that men abstain for 2 to 7 days before semen collection for fertility evaluation. The researchers conducted the current study to determine the effect of abstinence on sperm quality.

The researchers analyzed 9489 semen samples from 6008 men, comparing the concentration of sperm, percentage of normal sperm, percentage of motile sperm, and volume of semen, to the duration of abstinence before sperm collection.

Among the 3506 samples classified as oligozoospermic, defined as sperm concentrations below 20 million per milliliter, peak mean sperm concentration occurred after 1 day of abstinence and declined thereafter. Peak sperm motility also was seen after 1 day of abstinence, followed by a gradual decline. Percentage of morphologically normal sperm also peaked at 1 to 2 days of abstinence for oligozoospermic men. Total sperm count and total motile sperm count increased until day 4 of abstinence, and then declined.

Normozoospermic samples showed a nonsignificant decline in sperm concentration after up to 2 days of abstinence, followed by a gradual increase to a peak on days 6 and 7. Sperm motility increased after 1 day of abstinence, and remained high through day 7.

Among the men with normal sperm, peak normal sperm morphology was seen without abstinence, remained at a lower level up until day 10 of abstinence, and declined thereafter.

Dr. Levitas and colleagues conclude that, for optimum sperm motility and morphology, sperm should be collected from men with male factor infertility after 1 day of abstinence. While total sperm and motile sperm may increase after four days of abstinence, they continue, further prolonged abstinence will result in worse sperm morphology.

Seven days of abstinence will improve sperm quality among men with normal semen, the researchers add, but abstinence beyond 10 days is not recommended.

Fertil Steril 2005;83:1680-1686

Copyright © 2005 Reuters Limited. All rights reserved. Republication or redistribution of Reuters Limited content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters Limited. Reuters Limited shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon.