It is very hard (almost impossible) to prevent the EFS by yourself, because it is almost asymptomatic and you may not even know that you have it. The only sign of it is impossibility to conceive, but if you cannot get pregnant, then you don’t need prevention.
The disease already exists and needs to be treated. So, the only way to prevent the EFS is doing regular medical examinations. Especially if you belong to one of the risk groups: you are older than 35, you have some genetic diseases, you have PCOS or diminished ovarian reserve (a condition of low fertility characterized by 1): low numbers of remaining oocytes in the ovaries or 2) possibly impaired preantral oocyte development or recruitment).