when to start testing in luteal phase
When Are Progesterone Levels Checked? Your progesterone level is usually checked six to eight days after you ovulate (about day 21 of a day 28 cycle). This is because progesterone levels rise following ovulation, peaking five to nine days after ovulation. This is known as your luteal phase. After the midluteal period, your serum progesterone levels will begin to fall if the egg is not fertilized.