Gunderson S, et al. - The authors aimed at ascertaining if serum progesterone level on the day of hCG trigger was associated with positive hCG value after fresh embryo transfer in their center. They identified no association of serum progesterone levels on the day of hCG trigger with a positive hCG value after a fresh embryo transfer. Centers should perform their own analyses to determine if progesterone is an important predictor of outcome after fresh embryo transfer prior to changing historical practice patterns associated with fresh embryo transfer.