The level of progesterone fluctuates with the menstrual cycle, so the range of standard progesterone values varies somewhat from period to period. Progesterone levels are lowest during the menstrual period, when the ovaries secrete estrogen and progesterone after ovulation, resulting in a rapid rise in progesterone levels. The normal range of progesterone is less than 3.2 nmol/L during the follicular phase, and between 9.5 and 89 nmol/L during the luteal phase, with the majority of women having a progesterone level of around 65 nmol/L. If a woman is pregnant, then her progesterone will also change during the various periods of pregnancy. In early pregnancy, only the ovaries secrete progesterone, so progesterone values are mostly in the range of 63-95 nmol/L. In mid-pregnancy, the placenta has grown, so progesterone levels are at a particularly high level, mostly around 159-318 nmol/L.