How long are cats pregnant? Stages and kitten development week by week

Cats are pregnant for about nine weeks: on average 63 to 65 days from mating, with a normal range of 60 to 67 days. If your cat has not started giving birth by day 67, call your vet. The first visible sign is pink, enlarged nipples at around three weeks, and her belly starts to round from week four or five. Below you will find what happens inside her week by week, from fertilised egg to embryo to fully formed kitten, plus the signs to look for, how to care for her and when the birth becomes an emergency.

How long are cats pregnant?

A cat's pregnancy, or gestation, lasts 63 to 65 days on average. That is roughly nine weeks, or just over two months. Anything between 60 and 67 days counts as normal. A first litter takes just as long as later ones.

If you know when she mated, add 63 days to that date. A cat mated on 1 March will usually give birth between 3 and 5 May, and you should call your vet if nothing has happened by 7 May. Many owners only find out after the fact, because an unneutered cat that goes outside can mate without anyone noticing. In that case your vet can estimate how far along she is with an ultrasound scan or, later in pregnancy, an X-ray.

Cats are induced ovulators. Mating itself triggers the release of eggs, usually around 24 to 48 hours later. A queen often mates with several toms while she is in season, so one litter can have more than one father. That is why kittens in the same litter can look completely different.

Cat pregnancy stages: embryo and fetus development week by week

Every cat is slightly different, so treat these days as a guide. They count from mating. The timings for what happens inside her come from veterinary ultrasound research that followed pregnant cats day by day.

Week	Inside: embryo and fetus	What you notice and what to do
1	Ovulation 1 to 2 days after mating. Eggs are fertilised in the oviducts and start dividing as they travel towards the womb.	Nothing visible. Note the mating date if you know it.
2	The tiny embryos reach the womb around day 5 or 6 and spread out along both uterine horns. Implantation begins around day 12 to 14.	Still nothing to see. If the mating was unplanned, talk to your vet about your options now.
3	Each embryo sits in its own fluid-filled sac. A heartbeat can be seen on a scan from day 16 or 17. Limb buds appear around day 18.	Nipples turn pink and larger ("pinking up"). She may eat a little less or be sick once or twice.
4	By around day 26 the embryo has the recognisable shape of a kitten. From this point it is generally called a fetus.	Your vet can confirm the pregnancy by feeling her belly or with a scan. Ask which flea and worm treatments are safe now.
5	The skull, long bones, liver, stomach, bladder and lungs show up on ultrasound around day 30. The fetuses start to make small movements. Eyes and paw pads are visible by about day 35.	Her belly rounds out and her appetite grows. Weigh her once a week.
6	Kidneys, intestines and spine are visible by about day 40. A vet can sometimes tell the sex on a scan between day 38 and 43. The skeletons start to show on X-rays from around day 40 to 45.	She is clearly pregnant and very hungry. Switch gradually to kitten food.
7	Rapid growth. The heart chambers, the lens of the eye and the diaphragm are formed by around day 50, and the kittens make sucking and hiccup-like movements.	She starts looking for a nesting spot. Set up a quiet, warm birthing area now.
8	The stomach, gut and kidneys mature. The kittens put on weight and their coat grows.	Keep her indoors. Save your vet's and the out-of-hours number in your phone.
9	The kittens are ready to be born, usually weighing around 90 to 110 g each.	Restlessness, nesting, panting. She often stops eating in the last 24 hours. Call your vet if she has not given birth by day 67.

Weeks 1 and 2: fertilisation and the journey to the womb

After mating, the queen ovulates within a day or two. The eggs are fertilised in the oviducts, the narrow tubes between the ovaries and the womb. Each fertilised egg divides into a small ball of cells as it slowly travels down. Around day 5 or 6 these early embryos arrive in the womb, which in cats has two long horns shaped like a Y. The embryos spread out along both horns so that each one gets its own spot. From roughly day 12 to 14 they attach to the lining of the womb. This is implantation, and from here each kitten develops its own placenta.

You will not see anything on the outside yet. Even a scan rarely shows anything this early, although a vet with a high-resolution probe can sometimes spot the first fluid-filled sacs from around day 10 or 11.

Weeks 3 and 4: the embryo takes shape

This is the stage most people mean when they search for cat embryo development. Around day 14 the embryo becomes visible on ultrasound as a small thickening on the wall of its sac. By day 16 or 17 its heart is beating. Around day 18 it curls into a C shape and tiny buds appear where the legs will grow. Over the following week the head, spine and body become recognisable, and by roughly day 26 the embryo looks like a miniature kitten lying lengthways in the womb.

At the end of this stage the main organs have been laid down and the embryo is generally called a fetus. Outside, her nipples have turned pink and a vet can now feel the separate swellings in the womb. The best window for a scan is between day 25 and 35. A scan before day 21 can miss a pregnancy that is really there.

Weeks 5 and 6: the fetus grows and starts to move

From around day 30 the bones of the head and legs show up clearly on ultrasound, together with the liver, which fills much of the little belly, plus the stomach, bladder and lungs. The kittens start to make small sideways movements, and by about day 37 they move their heads, necks and legs. The eyes and the paw pads can be seen from around day 35. The kidneys, the intestines and the vertebrae follow around day 40, which is also when a vet can sometimes see whether a kitten is male or female.

The skeletons now hold enough calcium to show on an X-ray, from roughly day 40 to 45. Your cat's belly is clearly rounder and she is noticeably hungrier.

Weeks 7 to 9: growth and getting ready for birth

In the final third of pregnancy the kittens mostly grow. Their organs finish maturing: the chambers of the heart, the lens of the eye and the diaphragm by around day 50, and the stomach, gut and kidneys in the last ten days. On a scan you can even see them make sucking and hiccup-like movements. In the last week or two you may see or feel them move when she lies on her side.

Kittens are born with their eyes closed, and they open at around ten days old. An X-ray in the last week of pregnancy is the most reliable way to count how many kittens to expect.

Signs your cat is pregnant

For the first two weeks you will not see anything. These are the signs in roughly the order they appear:

1. She stops calling. After a successful mating she usually goes out of season. Some cats keep calling, though, and can mate again.
2. Pink, larger nipples. At around three weeks, sometimes nearer four, the nipples swell and turn a deeper pink. This is often the first physical sign.
3. A little sickness. Some cats eat less or are sick once or twice around week three or four. She should otherwise seem well.
4. A rounder belly. From week four or five. With only one or two kittens, her belly may hardly change.
5. Weight gain and a bigger appetite. A pregnant cat gains about 40 percent of her body weight over the whole pregnancy, and she is very hungry from about week six.
6. Behaviour changes. Many cats become more affectionate. Some withdraw a little, and a few become short-tempered with other pets in the last two weeks.
7. Nesting. From about week seven she looks for quiet, hidden spots such as wardrobes, boxes or under beds.

A human pregnancy test does not work on cats. Your vet can confirm the pregnancy by gently feeling her belly from three to four weeks or with an ultrasound scan. Please leave the feeling to the vet and do not press on her belly yourself.

Signs that do not belong to a normal pregnancy: lethargy, not eating for more than a day, repeated vomiting or bleeding before labour. Call your vet if you see any of these. Our guide on why a cat stops eating explains the other causes of a poor appetite.

Caring for a pregnant cat

See your vet early in the pregnancy. They can check she is healthy enough, advise on food and tell you which flea and worm treatments are safe. Many over-the-counter wormers are not licensed for pregnant cats, which we explain in our guide to the best cat dewormers. Never give medicines or supplements without checking with your vet first.

• Food: in the first half of pregnancy she needs no extra food. From about week six she gets much hungrier. Switch gradually to a food made for pregnant cats or a good kitten food, mixing it with her usual food over about a week. By the end of pregnancy she may need around one and a half times her normal amount. Keep her on it until the kittens are weaned.
• Small, frequent meals: the kittens take up space, so several small meals a day suit her better than two large ones.
• Weight: weigh her weekly. A cat that gets too fat can have a harder birth.
• Water: plenty of fresh water in more than one place.
• Handling: from about four weeks, only pick her up if she enjoys it, and support her back end.
• Indoors at the end: keep her inside in the last week or two, or she may give birth somewhere you cannot reach.

Preparing a birthing area

Set up a nesting spot at least two weeks before her due date, in a quiet, warm room away from the rest of the household and other pets. A sturdy cardboard box with a lid or a towel over the top works well. Make it big enough for her to lie stretched out with room for kittens, with an entrance low enough for her to step in but high enough to keep the kittens in for the first weeks. Line it with old towels or sheets you can easily change. Put food, water and a litter tray nearby, but not in the box.

Offer her a couple of options and let her choose. If she picks your wardrobe anyway, make that spot safe and leave her there.

Keep ready: clean towels, kitchen roll, a hot water bottle you can cover with a towel, a kitten feeding bottle or syringe with special kitten milk replacer (not cow's or goat's milk), and the phone numbers of your vet and the out-of-hours practice.

Signs of labour

• She becomes restless and keeps going back to her nest.
• She scratches at the bedding, pants, purrs loudly or calls out.
• She grooms herself a lot, especially around her rear and nipples.
• She usually stops eating in the last 24 hours.
• Her body temperature drops below about 37.8 °C (100 °F) within the day before labour.
• A clear or slightly red-tinged discharge in the last days can be normal.

The birth: what is normal

Most cats give birth without any help. Watch quietly from a distance, because disturbing her can make her pause her labour. Giving birth happens in three stages, and the second and third stages repeat for each kitten.

1. First stage. The womb starts to contract, but you will not see straining yet. She is restless and keeps visiting her bed. This can last up to 36 hours in a first-time mother and is usually shorter in a cat that has had kittens before.
2. Second stage. Contractions become strong and visible and she starts to strain. A water bag appears, and the kitten is usually born within 5 to 30 minutes of straining. The mother breaks the membrane, chews through the cord and licks the kitten clean to help it breathe.
3. Third stage. The placenta (afterbirth) comes out, usually just after each kitten, sometimes after two kittens. She often eats it, which is normal. Try to count one placenta per kitten.

Kittens usually arrive 10 to 60 minutes apart. Some cats take a break of up to 24 hours or even longer between kittens. That can be normal as long as she is relaxed, feeding the kittens she has and not straining. Litters are usually four to six kittens, often fewer for a first litter.

Only step in if you have to. If she does not remove the membrane, clear it from the kitten's head with clean kitchen roll, wipe the nose and mouth, and rub the kitten in small circles to help it breathe. If she does not deal with the umbilical cord, call your vet, who can talk you through it. Whenever you have had to help, ring your vet afterwards.

When it is an emergency

Call your vet or the out-of-hours vet straight away if you see any of these:

• She has been straining hard for 20 to 30 minutes and no kitten has appeared.
• A kitten is stuck halfway out and is not delivered after about 10 minutes.
• She has been in the first stage (restless, contractions, no straining) for more than 24 hours.
• There is dark, green or smelly discharge before the first kitten, heavy bleeding, or fresh blood for more than 10 minutes.
• She cries out in pain, seems exhausted or gives up pushing while kittens are still to come.
• She suddenly seems weak or collapses, or has a fever above 39.4 °C (103 °F).
• An hour has passed since the last kitten, she is still straining or unsettled, and you think more kittens are inside.
• Not all placentas have come out within four to six hours of the birth.
• She has not started giving birth by day 67.

Some breeds have difficult births more often, including the British Shorthair, Oriental breeds, Birman, Ragdoll, Abyssinian and Somali. If your cat is one of these, talk to your vet about the birth in advance.

After the birth, call your vet urgently if the mother trembles, walks stiffly or wobbles, or has a fit. This can be lactation tetany (also called eclampsia), caused by low calcium while she is feeding, and is an emergency. Also call if anything protrudes from her vulva, if she has a fever, if her discharge turns green or smells bad, or if a teat becomes hard, hot and painful. A red-brown discharge for up to three weeks after the birth is normal.

After the birth

Kittens should start feeding straight away. The first milk, colostrum, is full of antibodies, and kittens can only absorb them in the first 16 to 24 hours. If a kitten has not started suckling after 30 minutes, guide it gently to a nipple. If it still does not feed, call your vet, because newborn kittens need milk within two hours.

• Warmth: newborn kittens lose heat fast. Keep the room warm and the bedding clean and dry.
• Weight: newborns weigh about 90 to 110 g, should gain 10 to 15 g a day and double their birth weight by two weeks. Weighing them daily is the quickest way to spot a kitten that is falling behind.
• Peace and quiet: keep visitors and other pets away. A stressed mother may move or neglect her kittens.

Kittens cannot pee or poo on their own until about three weeks old, and they start weaning and using a tray at three to four weeks. Our guide to the best cat litter for kittens explains which litter is safe at that age. Kittens should stay with their mother until they are at least eight weeks old.

She can get pregnant again as soon as one to two weeks after giving birth, even while she is feeding. Keep her indoors and away from unneutered toms. Your vet can spay her once the kittens are about eight weeks old, and it will not affect her milk.

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