Mediterranean Diet Linked to Improved IVF Success Rates, Study Finds

The study utilized genetic sequencing to analyze the vaginal microbiota. Results showed that women who followed a Mediterranean diet exhibited more favorable microbial profiles conducive to implantation and maintaining pregnancy. Participants, who had been unable to achieve pregnancy after 12 months or more of unprotected intercourse, completed a validated questionnaire regarding their dietary habits. Those who successfully became pregnant had a microbiota dominated by Lactobacillus bacteria, associated with a stable and healthy vaginal environment.

Conversely, women who did not achieve pregnancy, particularly those with lower adherence to the Mediterranean diet, exhibited higher levels of Gardnerella vaginalis, a bacterium linked to microbial imbalances. The study also revealed differentiated microbial profiles between pregnancies that went to term and those that resulted in miscarriage, suggesting that the vaginal microbiome's composition, influenced by diet, may significantly affect both conception and pregnancy outcomes.

María Carmen Collado, a CSIC researcher in the Mainbiotics laboratory at IATA and the study’s lead author, noted that a lower diversity of vaginal microbes during pregnancy—unlike intestinal microbiota—does not necessarily indicate an imbalance; rather, it often reflects stability and health, particularly when Lactobacillus bacteria are predominant.

The research team categorized each participant's vaginal microbiota based on the predominant microorganisms, specifically examining Lactobacillus for its protective role in the vaginal ecosystem and reproductive health. Using a machine learning algorithm, they correlated dietary data with reproductive outcomes to identify patterns that favor pregnancy.

The findings suggest that dietary habits could serve as a complementary strategy to enhance the success rates of assisted reproduction treatments. This insight is particularly pertinent in today’s context, where Western lifestyles, characterized by stress, unhealthy eating, and antibiotic use, may disrupt vaginal microbiota balance and affect women’s reproductive health.

Key micronutrients and vitamins abundant in the Mediterranean diet—such as vitamins A, C, D, E, beta-carotene, calcium, and zinc—appear to protect against bacterial vaginosis, a common vaginal disorder in reproductive-aged women, as stated by Mar Gimeno, a gynaecologist at the Hospital Clínico Universitario de Valencia and a co-author of the study. Among participants who did achieve pregnancy, those who subsequently experienced a miscarriage demonstrated different microbial profiles with lower Lactobacillus presence.

Overall, the data imply that lifestyle modifications, particularly dietary changes, could serve as an additional strategy to improve fertility outcomes in assisted reproductive technology. Elia García Verdevio, a participating gynaecologist, emphasized that this research opens avenues for considering vaginal microbiota as a potential predictive marker for fertility success.

The high intake of fruits, vegetables, legumes, whole grains, fish, and olive oil typical of the Mediterranean diet plays a crucial role in modulating the vaginal microbiota. Collado remarked that adopting healthy dietary patterns may be a modifiable factor that improves the success rates of fertility treatments, highlighting that fertility is influenced not only by hormonal or genetic factors but also by diet and vaginal microbiota, which may serve as a useful biomarker for predicting artificial insemination success.