According to 2nd Chance, it takes roughly 6 to 8 hours for a mother cat to deliver an entire litter of kittens. Typically, the first kitten arrives around an hour after labor starts. There is often a period of 10 minutes to an hour between the arrival of each kitten.
There are two stages of cat labor. During the first stage of labor, cats may show symptoms such as rapid breathing, nesting, trembling and nipple discharge. The first stage of labor can last anywhere from 12 to 24 hours. During the second stage of labor, cats begin showing symptoms such as fluid around the genitals, straining and crying, according to Quality Cat Care.