Cats typically become pregnant shortly after they reach sexual maturity and start to experience heat cycles, which typically happen every two to three weeks. This means that during a three week estrus cycle, a cat can become pregnant and start a怀孕过程大约 10 天后交配的精子可以受精。交配成功后,受精卵大约需要十天时间才能通过输卵管移动到子宫。因此,怀孕期通常是从受精开始的约二十天(21天),或者更准确地说,在精子和卵子结合形成受精卵后的九周,即大约63至65天期间。