Aging / Linear models / Pregnancy / Humans / Fertility and Sterility / Female / Clinical Sciences / Ovarian Follicle / Estrogens / Adult / Public health systems and services research / Analysis of Variance / Fertilization in Vitro / Oocytes / Zona Pellucida / Pregnancy Rate / Female / Clinical Sciences / Ovarian Follicle / Estrogens / Adult / Public health systems and services research / Analysis of Variance / Fertilization in Vitro / Oocytes / Zona Pellucida / Pregnancy Rate