Progesterone, LC / MS (Endocrine Sciences)

Progesterone is a hormone that helps regulate the menstrual cycle and maintain pregnancy. Your levels depend on many factors including your sex, age, and where you are in your menstrual cycle.

When elevated: Elevated progesterone outside of luteal phase or pregnancy may indicate ovarian cysts, adrenal disorders, or exogenous hormone use. During pregnancy, abnormally high levels may suggest molar pregnancy or multiple gestation. When low: Low progesterone during the luteal phase may indicate anovulation, luteal phase defect, or impending miscarriage in early pregnancy. In men, very low levels are normal but extremely low levels may affect mood and cognitive function.

Progesterone influences recovery, bone density, and cardiovascular stability—all relevant to female athletes. Tracking progesterone across cycle phases helps contextualize performance variations, training tolerance, and injury risk, since luteal-phase elevations can affect thermoregulation, metabolism, and mood.