Luteal Phase

The two weeks following embryo transfer, when the embryo begins developing and implants in the lining of the uterus, is referred to as the luteal phase. During this time the ovaries, which contained the eggs, start producing a natural hormone referred to as progesterone. Additional progesterone is usually administered to help support the developing fetus and increase pregnancy rates. Progesterone is given by either injection or vaginal suppository. At the end of the two-week luteal phase, a pregnancy test is performed.