If a cat has been suffering heat cycles every 10 days to two weeks, and suddenly stops, it is very likely she is pregnant. Nipples Swell and Become Rosier in Color. Breeders call this pinking, and it may be the first physical sign you will see in a pregnant cat. Cat's Appetite Increases.
https://www.thespruce.com/signs-a-cat-is-pregnant-555419
If your cat was recently in heat and had access to a whole male cat, the likelihood that she is pregnant is very strong. A pregnant queen will display both physical and personality changes which will become more evident around three weeks after breeding. The gestation period for cats runs between 60 to 67 days.
https://www.thespruce.com/signs-a-cat-is-pregnant-555419
How long is a cat pregnant and what is the length of the gestation? It is said that this period will approximately last for about a month and 2-3 weeks. It roughly falls in the period of 57-70 days. But on an average, it has been seen that it will last for about 9 weeks.
http://www.ibuzzle.com/articles/how-long-is-a-cat-gestation-period.html
The Gestation Period. Let's assume you've decided to let your queen have her kittens. The second question is easier to answer than the first; a queen's gestation period typically runs from 57 to 69 days, with the average of 63 to 64 days. I like to use 63, because it is nine weeks, equating to human pregnancy average of nine months, making it easier to remember.
https://www.thespruce.com/so-your-cat-is-pregnant-552392
The gestation periods of other animal reveals that the length of the gestation period is largely a matter of the animal specie's size. Asian elephants have a gestation period of 645 days and African elephants 640 days. Dogs and other canines have a gestation period of about 60, which is also the period for cats. Even within the species of apes and monkeys gestation period seem to be a matter of size. For Rhesus monkeys it is 164 days and baboons 187 days.
http://www.sjsu.edu/faculty/watkins/gestation.htm
The length of a cat's pregnancy can be zeroed in at around 9 weeks, give and take a few days. Physical and Behavioral Changes. Now that we know the details of the gestation and how it is determined, let us move onto some of the important changes that take place in this period.
http://www.ibuzzle.com/articles/how-long-is-a-cat-gestation-period.html
Length of Gestation. The gestation period usually lasts for approximately 65 days. During this time the female grows larger and larger by day. If a cat is still pregnant after 69 days, it may be time to visit a veterinarian for professional advice. The same action should be taken if the cat begins the birthing process too soon.
http://www.professorshouse.com/gestation-period-for-cats/
A female cat can get pregnant when she’s as young as 4 months old, unless she’s been spayed to prevent that. Queens can keep going into heat every 2 to 3 weeks from the spring through the early fall, making them ready to reproduce more often than not. A cat’s pregnancy lasts about 63-65 days.
http://pets.webmd.com/cats/cat-pregnancy-gestation
How Long is the Gestation Period. The standard gestation period for cats is about 60 to 70 days, the equivalent of about two months. This will be a period of ups and downs for your pregnant cat. She may go from being contented and affectionate, to agitated, and back again during this time.
http://www.petyak.com/cats/kittens/articles/gestation-period-for-cats/
So, a cat can have kittens when she’s only 6 months old. The best way to find out is to make an appointment with your vet. He can confirm that kittens are on the way, and get an idea of how many, by feeling a cat's belly early on, doing an ultrasound in mid pregnancy, or doing an X-ray in late pregnancy. There are a few clues that you may notice, too. Her belly will get big around 30 days after she mates.
http://pets.webmd.com/cats/cat-pregnancy-gestation
how long is a cats gestational period
The gestational period for cats is lasts for 60 to 67 days.  