Inclusion Criteria:

Premenopausal group

• Age 40-48 at the time of original study recruitment.
• Regular menstrual periods for at least 1 year on no hormonal contraception at the time of their participation in the original study.

Postmenopausal group

• Age 52-60 at the time of original study recruitment.
• Confirmed menopausal status at the time of their participation in the original study: no menstrual periods for at least 1 year (but no more than 2 years).

Exclusion Criteria:

• History of hysterectomy.
• History of surgical, chemical, or radiation-induced menopause (i.e., oophorectomy, aromatase inhibitors, chemotherapy for cancer treatment, or radiation therapy).
• Use of any drug that can affect estrogen production or signaling (e.g., GnRH agonists and antagonists, estrogen receptor modulators, etc.).
• Use of systemic estrogen and/or progesterone (oral contraceptives, contraceptive implants, hormone replacement therapy).
• Use of non-hormonal contraceptive methods that can affect the regularity of menstrual cycles (e.g., intrauterine devices).
• History of hypothalamic or pituitary disease (e.g., pituitary adenomas, empty sella, pituitary surgery, hypothalamic masses).
• Patients who denied future use of biological samples or further contact from the previous listed IRBs.

Eligibility last updated 4/18/22. Questions regarding updates should be directed to the study team contact.