As reported in the New York Times two studies suggest that sex alters a woman’s immune system in ways that affect her chances of conceiving.
According to one of the new studies, published in September in the journal Fertility and Sterility, the sexually active women displayed heightened levels of a certain immune cell when their reproductive systems were preparing to release an egg but before they were able to become pregnant. Later in the menstrual cycle, when conception was possible, these women developed higher levels of a different type of immune cell — one known to help a body recognize and ignore nonhazardous foreign cells, like those in a fetus. There were no similar changes in the immune systems of the abstinent women.
The other study, published in Physiology and Behavior, found other immunological differences. Sexually active women early in their cycles developed more antibodies of a type that lives in the mucus lining the reproductive tract and represents a threat to sperm and fetuses. Levels of these antibodies dropped later in the cycle, while the numbers of a different germ-fighting antibody in the blood but not in the reproductive tract grew.
It’s also not clear how the immune system knows someone is having sex. There may be messages from the brain or extra changes in hormones.
But after reading this why are you still looking at your computer when you could be doing something proactive that may increase your chances of conceiving?