Parturition
Tina, by AZAdam
Parturition begins with a series of uterine contractions that lead to expulsion of the first fetus. The placenta for each fetus will often pass shortly thereafter. As you see here, the mother licks away the membranes to clean the kitten, and she also may eat the placenta. The kitten will be encouraged by the mother to nurse.
The process will continue until all of the kittens have been born. At that time the contractions will cease, and the mother will continue to clean and nurse her young.