How Can I Tell How Many Weeks Pregnant Is My Cat?

You'll know how many weeks she is because week by week she gets fater and the first couple weeks she doesnt look different and the 5 or 6 week she has a kinda big round belly and 2 days befor she gives birth she will start perducing milk, vomiting, follow around so she knows wear she wants to have her kittens. Hope This Helps :)

Pregnancy in the cat lasts 63 days, or 9 weeks.  You will not see any signs of pregnancy until 3 weeks.  Her nipples will become a dark pink colour, she may sleep more and show more affection.  After 4 weeks, weight gain and abdominal enlargement may be noticeable.  After 6 weeks, her mammary glands will being to enlarge.  About 1 week before delivering her kittens, she will start showing nesting behaviour.  You should prepare a nest for her, rather than have her select a drawer, or laundry basket for herself.  This is also the time you should begin taking her rectal temperature.  Ideally this should be done 3 times daily.  24 hours before delivery her rectal temperature will drop by 1-2 degrees Celsius.  This drop will only be noticeable if you have established her baseline temperature by taking her temperature regularly.  Signs that delivery is imminent is restlessness, calling, vomiting, pacing, and nesting.

You usually can't really know how pregnant your cat is for sure but you should schedule an appointment with your vet so they can officially tell you