House-Cat Gestation Period for Pregnancy

The cat gestation period or cat pregnancy lasts about nine weeks. It is normal for cat gestation to be anywhere from 57 to 65 days. The pregnant cat, also known as a "queen," experiences various physical changes as she progresses through the three trimesters of gestation. A pregnant cat normally delivers a litter of two to six kittens, with as many as eight possible.

  1. First Week

    • Once the female cat's eggs are fertilized by the male's sperm, the eggs begin to form a mass of cells. The cells grow and divide. The cell mass is called the morula when 16 cells are formed. This morula moves into the cat's uterus, planting itself on the uterine wall. The number of morulae that implant and survive in the uterus will be the number of kittens in the litter. It takes about five days for the morula to reach the uterus, and it connects to the uterine wall within 14 days of fertilization.

    Second Week

    • As the morulae develop, forming the head and body of the kittens, they become known as embryos.The embryos live within two sacs of fluid known as the allantois and amnion. The amniotic fluid is made up of the nutrients the embryos need to develop, such as salt, sugar, fat, protein and water.

    Third Week

    • As the gestation period continues the placenta is formed. The placenta attaches the embryos to the mother's bloodstream, providing them with nutrients and oxygen. The placenta also removes the bodily waste from the developing embryos. After the organic structure of the embryo has formed, it then becomes a fetus. This happens three weeks after fertilization; the mother cat still shows no outward signs of pregnancy.

    Second Trimester

    • During the next three weeks, the fetus develops all its organs, circulatory system, muscular system and skeletal system. The mother cat's umbilical cord continues to bring nutrients to the fetus. This is an important part of the gestation period because all the organs that are needed for a healthy kitten are developing. The fetus will begin moving, kicking and turning its head. It can also swallow at this point. The mother cat develops a slight pouch during this time and a veterinarian will be able to feel the fetuses by examining the cat's belly.

    Third Trimester

    • At this point in the cat's gestation period, the fetus has all its major organs and bodily systems. Now the queen's nourishment to the fetus is used for growth. During the last three weeks of the cat's pregnancy the fetus will grow by seven times until it can survive outside its mother's body. The kitten can now open its eyes and hear sounds, and grows claws. The mother cat will be noticeably larger now.

    Labor

    • When the queen begins labor, she howls and acts nervous. She starts looking for a dark, secluded area. Her temperature will drop up to two degrees in the 24 hours before delivery. The howling and restless behavior can last from 12 to 24 hours and then delivery will begin. Kittens can be delivered within only a few minutes of each other or can be up to an hour apart.