Progesterone Hormone Test

Progesterone, a female sex hormone, primarily prepares the uterus for pregnancy and maintains it during gestation. The placenta starts producing progesterone at 12 weeks of pregnancy, and its levels peak in the midluteal phase of the menstrual cycle. In non-pregnant women, the corpus luteum produces progesterone, which is the best indicator of ovulation.

This test can be used as part of a fertility study to confirm ovulation, evaluate corpus luteum function, and assess the risk of early miscarriage. Depending on what a health professional is after when asking for this test, multiple samples maybe needed throughout the cycle. Progesterone production by the ovaries is low during the follicular (first) phase of the menstrual cycle. After ovulation, progesterone levels rise for 4 to 5 days before falling. During pregnancy, progesterone levels gradually increase from week 9 to week 32, often reaching up to 100 times the level in non-pregnant women. Progesterone levels are higher in twin pregnancies compared to single pregnancies. Combined with ß-hCG, serum progesterone levels help differentiate between normal uterine pregnancy and abnormal or ectopic pregnancy.