Fecal transplants from old mice have been found to boost fertility and ovarian health in younger mice, according to a recent study published in the journal Nature Aging. The surprising results suggest a direct link between gut health and reproductive health, with potential implications for understanding how the microbiome influences ovarian function and fertility in humans.
The study, led by biologist Bérénice Benayoun from the University of South California Leonard Davis School of Gerentology, initially expected that fecal transplants from older mice would age the ovaries of younger mice prematurely. However, the opposite was observed, indicating that some intriguing biology was at play.
The microbiome, which consists of bacteria, organisms, and viruses living inside and on the body, is known to play a role in various aspects of health, including reproduction and fertility. Fecal transplants aim to replace “bad” bacteria in the gut with “healthy” bacteria from a donor’s feces. While the benefits of this procedure in humans are still being researched, it is used in certain cases to treat bacterial infections and other conditions.
In the study, older female mice in the estropause stage, similar to menopause in humans, were found to have rejuvenated ovarian cells and improved reproductive success after receiving fecal transplants from their older counterparts. This effect may be due to a communication pathway between a group of gut microbes called the estrobolome and the ovaries, which deteriorates with age. Younger mice receiving these transplants may enhance this communication to compensate for the breakdown, thereby boosting their reproductive health.
While the study’s findings in mice cannot be directly applied to humans, they suggest that ovarian function is adaptable and influenced by the microbiome. Further research is needed to identify specific gut organisms that communicate with the ovaries in humans. However, the discovery opens up possibilities for designing ovarian-supporting probiotics based on these findings.
In conclusion, the study sheds light on the intricate relationship between gut health, the microbiome, and reproductive health. By understanding how fecal transplants from older mice can positively impact fertility in younger mice, researchers may uncover new avenues for improving ovarian function and fertility in both animals and humans.

