The main cause is age. There is an inversely proportional relationship between age and the number of eggs available to mature.
However, there are other factors that can negatively affect ovarian reserve, such as medical treatments, drugs, obesity, endometriosis, etc.
Read the full article on: Can a Woman’s Egg Count Be Measured with a Blood Test? ( 59).

Zaira Salvador
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI)
License: 3185-CV