More sex = Better fertility

According to a study published in Fertility & Sterility and reported in the Washington Post more sex, even not at the time of ovulation, may increase the chance of pregnancy.

For centuries, women have used the calendar method for getting pregnant (or for avoiding getting pregnant) based on the idea that having sex on or around the days they are ovulating increases their chances of conception.

But what about the “off” days? According to two studies recently published in the journals Fertility and Sterility and Physiology and Behavior, having more sex, any time may boost fertility.

It has to do with the immune system.

Tierney Lorenz, a visiting research scientist at the Kinsey Institute at Indiana University, theorizes that sex appears to trigger physiological changes that may be preparing a woman for pregnancy.

In the first study, which involved 30 women, Lorenz and her colleagues found sexually active women experienced greater changes in what are known as “helper T cells,” as well as the proteins that T cells use to communicate. In the second, which involved 32 women, the researchers found similar differences in how antibody levels fluctuate between the two groups.

Helper T cells are a key part of the body’s immune response, activating cells that defend the body against microbes. Antibodies, or immunoglobulins, are secreted by white blood cells and fight infection from bacteria, viruses and other attackers.

“We’re actually seeing the immune system responding to a social behavior: sexual activity,” Lorenz said in a statement. “The sexually active women’s immune systems were preparing in advance to the mere possibility of pregnancy.”

Even if this theory is not correct, having more sex may not help, but at least it wouldn’t hurt.