Cats are excellent breeders, and will often be pregnant after just one “encounter.” Dr Eloise Bright is a veterinarian for Love That Pet says "Cats are incredibly efficient breeders, so if you have an unspayed female cat who has access to male cats, the odds are she will get pregnant twice a year.” Between Spring and Autumn, cats go into heat every 2-3 weeks, meaning they're ready to breed more often than not. And cats start early - kittens as young as four months old can get pregnant.
The full term of a cat pregnancy is around 63 days or nine weeks. You're unlikely to spot any signs in the first few weeks. After that, you'll see some noticeable change in their behaviour and appearance.
4 Cat pregnancy signs
1# Darkened Nipples
This happens around 3 weeks into the pregnancy. Vets refer to this as “pinking up”, and so your cat's nipples will become dark crimson colour. They may also get noticeably bigger. If the nipples swell but remain the same colour, then your cat is probably just in “heat.” Cats don't start producing milk until after the birth, although you might see a milky discharge coming from the nipples.
2# Morning Sickness
Just like a pregnant human, cats can suffer from morning sickness. The severity and frequency of the symptoms can be dramatically different from cat to cat, and some won't experience morning sickness at all. It usually starts in the earliest phase of the pregnancy and morning sickness in itself is nothing to worry about. When a cat is pregnant, their brain releases extra hormones that can upset the bodies natural balance; this normally settles down after a few weeks. If it does continue, or your cat seems particularly unwell, take him/her to a vet.
3# Swollen Belly
You might think that this one is a bit of a giveaway, but a swollen belly is easy to overlook. It begins around the 30-day mark. The belly will start to swell and distend, or "hang-low." Although these signs sound pretty obvious, they're harder to spot in cats who are overweight or have lots of fur on or around their belly. And there's also the change that you might not notice the extra weight. Depending on the number of kittens, a cat will gain around 2-4 pounds. A pregnant human can pile on an extra 35 pounds!
A few weeks before the big day, your cat will start “nesting.” It's an instinctual behaviour caused by an increase of a pregnancy called estradiol. It encourages the mother to find a safe where she can give birth to her kittens. Out in the wild, nesting protects mum and her kittens from any predators.. It also creates a sense of family structure and belonging, helping the mother to bond with new kittens.
A “nesting” domesticated cat will find a quiet and safe place where she can prepare for the arrival of her kittens (the bottom of your wardrobe is a common spot for nesting cats.) She may also become hostile towards any other family pets. She isn't being mean; she just wants to keep her kittens safe.
Get the good news confirmed
If you think your cat is pregnant, the best thing to do is get them checked by a vet. Depending on the stage of the pregnancy, your vet may perform an ultrasound or an x-ray. Ultrasounds can spot the kittens after the first 21 days of pregnancy, although they can't show how many kittens are on the way. X-rays can only spot the kitten after 41 days (this is when their little skeletons begin to form.)
And don't worry about radiation from the x-ray. Plus, it is the best way of knowing how many kittens you need to prepare for! But just to give you an idea, the average litter size is four kittens.
Cats are independent and self-sufficient creatures. Most of them are more than capable of managing the pregnancy themselves. In fact, many of them do! The signs of a cat pregnancy are not glaringly obvious, and many owners can easily overlook them. But at least know what to keep an eye out for. And if you did see any of any the cat pregnancy signs, it’s always best to get kitty checked over by a local vet.