Looking to improve your fertility? You may be in luck. According to a press release from Eurekalert, a new study from researchers at Indiana University has discovered a simple way to increase a woman’s chances of conception – and it’s 100 percent natural.

The study showed that women who engage in sexual activity experience physiological changes that increase their chances of getting pregnant, even when they are outside their normal window of ovulation. The findings could lead to a more informed recommendation for how often couples trying to conceive should engage in sexual intercourse. The study also showed that sex could influence immune health in people suffering from autoimmune disorders.

The study’s findings were published in the journals Fertility and Sterility and Psychology and Behavior. It was carried out by lead author Tierney Lorenz, a visiting research scientist at the Kinsey Institute. Co-authors Julia R. Heiman, a professor in the Department of Psychological and Brain sciences, and Gregory E. Demas, a professor in the Department of Biology at Indiana University joined Lorenz to complete the research.

According to Lorenz, who is also working with the Center for Integrative Study of Animal Behavior at Indiana University, recommending that couples trying to get pregnant have sexual intercourse on a regular basis is a common practice. Doctors recommend it even when women aren’t at their peak of fertility, although it remained unclear why this was so.

The new study offers insight into how sexual activity can cause the body to promote certain immune system responses that can help the body prepare for conception. For years, doctors were perplexed by the additional benefit to fertility brought about by sexual activity that didn’t occur during a woman’s fertile window. The new research sheds light on the specific changes that occur during this activity.