Fertility may be enhanced by more sun exposure, finds new study
Women who are late to find a partner or who put a focus on a career, usually have a harder time getting pregnant in their 30s and certainly in their 40s as they become less fertile. But a new study suggests the sun might give your egg follicles a boost.
A research team looked at seasonal fluctuations in AMH (anti-Müllerian hormone) levels. Their pioneering study revealed that during the summer, women of late reproductive age — between the ages of 30 and 40 — experience increased secretion of the hormone from their ovaries. This phenomenon is suggested to be attributed to heightened exposure to ultraviolet (UV) radiation from the sun.
“The ovaries secrete the anti-Müllerian hormone, and its level in the bloodstream is linked to ovarian function,” explains Dr. Ruth Percik from the Institute of Endocrinology at Sheba Medical Center. The results of the study were published in the journal Steroids. It may be used to help improve IFV success rates.
She adds: “While the hormone level is specific to an individual woman at a given point in time and does not provide a definitive assessment of the status of her fertility, evaluating its value, trend, and comparison to the age group is the best indicator of fertility that we have. For this reason, every woman who wants to get pregnant, or is trying to, is sent for an AMH test. In Israel, all of these tests are directed to the central laboratory in Sheba. Our research group investigated the seasonal variability of the AMH tests in order to gauge how the ovaries respond to UV radiation.”
The researchers compared the AMH results of 2,235 Israeli women to the recorded levels of UV radiation. For younger women, aged 20-29, no statistical relationship was found between UV exposure and AMH level. On the other hand, among older fertile women, aged 30 to 40, a statistically significant seasonal pattern emerged: These women, whose egg reserves are in decline, responded positively to sun exposure.

Dr. Carmit Levy, Tel Aviv University
The groundbreaking research was led by Prof. Carmit Levy of the Department of Human Genetics and Biochemistry, in a team effort of Ph.D. student Roma Parikh and Prof. Yftach Gepner of the School of Public Health, all from the Faculty of Medicine at Tel Aviv University.

“This is a preliminary, pioneering human epidemiological study,” says Prof. Levy, “and we need to be cautious about inferring a causal relationship between fertility in women and exposure to UV radiation.
“Our research suggests that the female reproductive system is indeed more fertile in the summer, but we still have no information on the mechanism or actual success rates.”
Particularly interesting is the absence of this effect among younger women in their 20s. According to Dr. Percik, this may be attributed to the ample egg reserve found in young women. “Based on my interpretation of the findings, women at the onset of their reproductive age are less in need of signals from the sun, which affect hormonal pathways that have not yet been sufficiently studied.
This effect was most pronounced among women aged 35 and older. One caveat: Exposure to the sun’s UV radiation should always be done in moderation, and further research is required in order to determine whether such exposure actually helps fertility, and how much exposure is needed. And just to be safe, you can make your own organic sunblock using this recipe.


