Fostering a Pregnant Cat: 63 Days, 2 Boxes, 2 Checks

A pregnant queen needs 63 days of counting, 2 nest boxes and 2 checks a day. That is the job. Fostering a queen is easier than bottle-feeding 4 kittens and harder than fostering a healthy adult, because failures arrive without warning: a cat fine at 8 a.m. can be straining at 10 a.m., and a newborn can be cold and quiet 90 minutes after birth.

63 days, minus the part nobody knows

Gestation runs 61 to 65 days from mating, with 63 to 64 as the usual figure. If the mating date is unknown, the estimate carries plus or minus 7 days, so plan for the early edge: a queen who arrives at day 50 may deliver in 9 days, not 13. Book the vet visit for day 55 to day 58, when the abdomen is easy to palpate and an ultrasound can count fetuses. Knowing whether you expect 2 kittens or 6 changes the supplies and the weaning plan.

Write the dates in 3 columns: day of gestation, predicted date, what should be happening. A queen at day 45 needs about 25% more calories than she did at day 20; by day 60 that rises to 50% more, split into 4 to 6 small meals instead of 2 large ones.

Two boxes, about 2 meters apart

Cats want a choice of exit route, so 1 box is not enough. Set up 2 whelping boxes at day 50, roughly 2 m apart in the same quiet room, and let the queen pick. Each should be at least 45 by 45 cm with 15 cm walls, a front lip low enough for a 4-week-old to climb, and bedding you can wash at 60 Celsius. Put one in a closet corner and one against a wall in the open; most queens choose the enclosed box, and the second is the fallback if the first is soiled during labor.

Add a heat source covering no more than half the floor, at 29 to 32 Celsius for the first 2 weeks, so kittens can crawl off. A room at 22 to 24 Celsius with a covered box is usually enough; a pad over the whole floor is how kittens get overheated and dehydrated.

Twice a day, on paper

Two checks a day, 12 hours apart, at fixed times so a change stands out. Mornings: appetite, litter box, vulvar discharge, behavior. Evenings: weight, mammary glands, and a 60-second watch for fetal movement.

Gestation day	Weight change	Appetite	Action this week
0 to 21	+0.3 to 0.5 kg	100% of usual	No food change, no belly handling
22 to 42	+0.4 to 0.6 kg	125%	Kitten food, 4 meals a day
43 to 55	+0.3 to 0.4 kg	125% to 150%	Set up 2 boxes, vet check day 55 to 58
56 to 63	+0.1 kg	150%	Night checks, 2 per day
64 to 70	0 kg, plateau	150%	Call the vet, 4 to 7 days overdue

Labor: the numbers that mean phone the vet

Stage 1 runs 6 to 12 hours of restlessness and purring, sometimes vomiting. Stage 2 is active straining, and a kitten should arrive within 30 minutes of hard contractions. Call if she strains 30 minutes with nothing, if more than 2 hours pass between kittens while contractions continue, or if a kitten is visible in the canal for 5 minutes with no progress. A placenta should follow each kitten within 15 minutes; count them, because a retained placenta means a same-day visit.

Newborns weigh 90 to 120 g and gain 10 g a day for the first 2 weeks, doubling birth weight by day 14. Weigh each kitten daily at the same time on a 1 g scale. A kitten that loses 10% of birth weight in 24 hours, feels cool, or is pushed away from the group needs warming and a vet call the same day.

Three items to hand over

Handover is where foster care fails, because the queen leaves with 6 weeks of history in one person's head. Put it on 1 page, 3 items.

Medical and dates: mating or intake date, due window plus or minus 7 days, vaccines and deworming given during pregnancy, any discharge or fever, and the day 55 to 58 report.
Temperament: whether she allows belly touch, whether she hides when the door opens, how she reacts to other cats, and the 2 or 3 things that calm her. This predicts week 1 better than any shelter score.
Kittens and supplies: number born, birth weights, current weights, preferred nipple, plus leftover kitten food, scale and heat pad.

Weeks 0 to 8, and the window that matters

The socialization window runs from about week 2 to week 7. Handle each kitten 3 to 5 minutes a day in 2 sessions with hands, a soft cloth and normal household sounds; a litter of 4 to 6 means every kitten gets its own minute, not a group cuddle. Weaning starts at 4 weeks with gruel, and by 6 weeks they should eat solid kitten food 4 times a day. Desexing is usually booked at 8 to 12 weeks or 1 kg.

Keep the queen on kitten food until weaning ends: she is feeding 4 to 6 kittens and at peak needs 2 to 3 times maintenance calories. Weigh her weekly, because a queen losing more than 5% of her weight in 1 week is not eating enough for the litter she has.

Cost, before you say yes

Most of the bill lands in the first 3 weeks: whelping box 30 to 60 USD, 1 g scale 20 to 40 USD, heat pad 25 to 45 USD, milk replacer 20 to 30 USD per tin if needed. The day 55 ultrasound is typically 80 to 150 USD, and a cesarean runs 600 to 1,500 USD. Many shelters cover vet costs for registered foster homes; confirm that in writing, then check the first-year cost breakdown so the adopter is not surprised at week 6.

When to call the vet tonight

Green or brown discharge before day 57, fever over 39.5 Celsius, straining with no kitten for 30 minutes, a kitten stuck in the canal, more than 2 hours between kittens, a retained placenta, a queen ignoring her kittens for 30 minutes, or any kitten that is cold, limp or refusing to suck: 8 calls that should never wait for morning.

Before the queen arrives

Confirm the due window and add 7 days on both sides.
Set up 2 boxes by day 50, 2 m apart, 15 cm walls, washable bedding.
Print a 3-column check sheet and fill it twice a day at fixed hours.
Buy a 1 g scale and weigh kittens before the first feed.
Write the 3 handover items on 1 page and give a copy to the adopter, not only the shelter. If the placement is still open, read foster-to-adopt for how the trial runs.

Frequently asked

Can I foster a pregnant cat with other cats at home?

Yes, if you can keep her in a separate room from week 5 onward and wash your hands between groups. Queens are usually tolerant of resident cats but want isolation before birth, and the last 2 weeks are when she will pick a closet and defend it. Keep introductions closed until the kittens are at least 4 weeks old.

How do I know the due date if nobody saw the mating?

You do not, which is why the estimate is a window of plus or minus 7 days around day 63. An ultrasound at day 55 to 58 can confirm live fetuses and give a rough count, and the appearance of the nipples plus a 1 Celsius temperature drop usually signals labor within 24 hours.

What do I do if a kitten is born cold?

Dry it, warm it against your skin or under a lamp at a safe distance, and do not feed a cold kitten until it is warm, because a cold gut cannot digest. Call the vet the same day, keep the kitten with the queen if she accepts it, and weigh it every 2 hours until it gains.