Inclusion Criteria:  Women who underwent first dose or complete cycle of covid-19 vaccine, regardless of the type of vaccine used.  Exclusion Criteria:  Women undergoing any kind of hormonal therapy, including combined oral contraceptives, oral/vaginal progestins, intrauterine devices, GnRH-analogues, aromatase inhibitors, hormonal replacement therapy in menopause; Surgical menopause (hysterectomy and/or bilateral oophorectomy); Breastfeeding.