The PCT should be performed 8 hours after intercourse and 1 to 2 days before the predicted time of ovulation, when there is maximum estrogen secretion unopposed by progesterone.

• 性交后试验应该在性交后8小时进行，并比预测的排卵期提前1-2天，此时雌激素达最大而孕激素未明显分泌。