Traditionally a two day period of abstinence has been recommended prior to ovulation or an IUI. A recent study in the March 2010 issue of Fertility & Sterility suggests that shorter period of absintence results in better pregnancy rates. In this study an ejaculatory abstinence period of less than 2 days before IUI produced the highest pregnancy rates per cycle compared with longer intervals of ejaculatory abstinence. This higher conception rate occurred despite a lower total number of motile spermatozoa inseminated.
This may be explained by the observation that shorter periods of abstinence can result is less fragmentation in the DNA of the sperm. This is another demonstration of the fact the quality can be more important than quantity. It's important that those trying to conceive consult their doctors to determine the best period of abstinence in their case.