Studies on fertility
One study was published in the journal Fertility and Sterility and the other in the journal Physiology and Behavior. Each study looked at data on the menstrual cycles of 30 healthy women of child-bearing age. Half were sexually active and the other half were abstinent, having no sex whatever.
The data examined in the study that was published in Fertility and Sterility showed the supply of “helper T cells” were increased in the women who were sexually active, regardless of their having sex during ovulation or at another time during the month. Those helper T cells boost a woman’s immune system and increase her fertility.
The data examined in the study published in Physiology and Behavior showed immunoglobulin A antibodies were increased in the sexually active women but were not increased in the abstinent women; an increase in those antibodies is another physiological event that boosts a woman’s immune system and increases her fertility.
Sex outside ovulation
Tierney Lorenz, from the Kinsey Institute at Indiana University and one of the three authors of the study published in Physiology and Behavior said that their results are “a new answer to an old riddle” of how sex outside of ovulation manages to help with achieving a pregnancy.
“It’s a common recommendation that partners trying to have a baby should engage in regular intercourse to increase the woman’s chances of getting pregnant— even during so-called ‘non-fertile’ periods— although it’s unclear how this works,” Lorenz said in a press release.
“This research is the first to show that the sexual activity may cause the body to promote types of immunity that support conception.”
Lorenz said effects on a woman’s body from sexual activity help her to solve a problem that must be solved for a pregnancy to occur: to wit, to keep healthy, her body is accustomed to fending off foreign invaders but when it comes to sperm or a fetus if her body treats them as an invader there will be no pregnancy.
Because a woman engages in sexual intercourse, again regardless of the time of the month in which the sex takes place, it is more likely that her body will not detect sperm or a fetus as a foreign invader, thus making it more likely a pregnancy will occur.
That is good news for a woman looking to become pregnant — and good news for the man in her life, too.
