Most of the weight arrives in the last third of pregnancy. A queen carrying 4 kittens gains 20 to 30 percent of her pre-breeding weight across 9 weeks, under 5 percent of it in the first 4 weeks, and 3 to 5 percent per week in the final 2 weeks. A weight that does not move for 2 consecutive weekly checks is the single most useful early warning you can buy for 30 dollars, because it precedes most visible signs of a failing pregnancy.
The Shape of the Curve
Feline gestation runs 63 to 65 days from ovulation, with a normal range of 61 to 72 days because mating dates are only an estimate. The curve is not linear: weeks 1 to 4 are almost flat, week 5 turns upward, and weeks 8 and 9 carry most of the gain. The reason is fetal mass. A kitten weighs 5 to 10 grams at day 30, 60 to 90 grams at day 45, and 90 to 120 grams at birth, so roughly 70 percent of fetal weight is laid down in the last 3 weeks. Add placenta, fetal fluids and mammary growth, and the last 21 days account for 15 to 20 points of the total 25.
Week-by-Week Targets for a 4 kg Queen
The table assumes a 4 kg queen at breeding and 4 kittens. Scale every kilogram figure by her actual weight divided by 4; litter size moves the total, not the early weeks.
| Week | Cumulative gain | Gain that week | Weight at 4 kg start | What to check |
|---|---|---|---|---|
| Week 1-2 | 0-2% | 0-40 g | 4.00-4.08 kg | appetite only |
| Week 3-4 | 2-5% | 40-60 g | 4.08-4.20 kg | teats pink by day 21 |
| Week 5 | 8-11% | 120-160 g | 4.32-4.44 kg | abdomen widens |
| Week 6 | 13-16% | 150-200 g | 4.52-4.64 kg | ultrasound count |
| Week 7 | 17-20% | 140-180 g | 4.68-4.80 kg | nipple development |
| Week 8 | 22-26% | 180-240 g | 4.88-5.04 kg | X-ray skeleton count |
| Week 9 | 26-30% | 160-200 g | 5.04-5.20 kg | nesting, temperature |
Why the First 4 Weeks Stay Under 5 Percent
Early pregnancy is hormonally quiet and energetically cheap: the embryos are free-floating until about day 12 to 14, implant around day 14 to 18, and the whole conceptus at day 28 weighs under 30 grams. A queen that gains 400 grams in week 2 is not pregnant, she is overfed, and that matters because fat laid down before implantation is hard to lose during lactation. Keep her on maintenance, 1.2 to 1.4 times resting energy requirement, through week 4, then raise intake gradually from week 5 to 1.2 to 1.5 times RER. The energy plan behind that ramp, including grams per day, is in feeding the pregnant queen.
Why the Last 2 Weeks Run 3 to 5 Percent a Week
Three things stack at once: fetal growth, mammary tissue, and 150 to 250 ml of fetal fluid. At 4 kg, 3 to 5 percent is 120 to 200 grams a week, and it happens on a stomach that is being compressed by the uterus, which is why meal size drops while calorie need rises. Feed 4 to 6 small meals from week 7, keep food available overnight, and do not switch diets in the last 10 days; a sudden change at day 55 produces diarrhea at exactly the wrong moment.
How to Weigh So the Number Means Something
Use a kitchen or baby scale with 10 gram resolution, weigh at the same time each morning before the first meal, and record to the nearest 10 grams. A human scale held in arms carries 200 to 400 grams of error, which is larger than an entire week of gain in early pregnancy. Weigh weekly from the mating date to week 6, then twice weekly in weeks 8 and 9. Also measure abdominal girth at the widest point with a soft tape: 2 to 4 cm of increase per week from week 5 onward is normal, and 0 cm for 2 weeks is the same red flag as a flat scale.
A Stall of 2 Weeks Means Recheck, Not Patience
Two consecutive weekly checks within 20 grams of each other, between weeks 5 and 8, is the trigger. Book an ultrasound within 3 to 7 days rather than waiting for the next scheduled visit. The differential is short: fetal resorption, fetal death with mummification, a litter of 1 or 2 rather than 4, or a queen who is simply underfed because she cannot eat enough in 2 meals. Resorption usually shows as a weight drop of 100 to 200 grams plus a return of vulvar discharge. A mummified fetus can sit for weeks and then cause dystocia at term, so an X-ray at day 55 to 60 to count skeletons is worth the 120 to 250 dollars. An ultrasound at day 30 to 35 counts sacs; an X-ray at day 55 to 60 counts skulls, and the skull count is the number you can trust.
Gaining Too Much Is Also a Problem
A gain above 35 percent, or a body condition score of 7 or more on the 9-point scale, raises the odds of a difficult birth and of a queen who cannot reach her kittens to clean them. Fat in the pelvic canal does not stretch. If she crosses 32 percent before week 8, cut treats first, then reduce the fat content of the diet by about 10 percent, and keep protein at 35 to 40 percent of dry matter so mammary tissue still has building material. The handover from pregnancy energy targets to lactation ones is laid out in nutrition from pregnancy into lactation.
What Happens at Birth to the Number
Expect a 10 to 15 percent drop within 24 to 48 hours of kittening: 4 kittens at 100 grams, plus placenta and fluid at 150 to 250 grams, comes off a 5.0 kg queen and leaves 4.35 to 4.50 kg. That is normal and should not be corrected with extra food in the first 48 hours. Weigh her at 24 hours and again at 7 days; a further loss beyond 15 percent of the pregnant weight points to metritis or mastitis rather than underfeeding, and both need a vet the same day. If a placenta is still not out 24 hours after the last kitten, call the vet that day; a retained placenta is an emergency, not a wait-and-see item.
Cost of Doing It Properly
A 10 gram resolution scale costs 25 to 45 dollars, weekly weighing costs nothing after that, one extra ultrasound is 80 to 180 dollars, and an X-ray count at day 55 to 60 is 120 to 250. Against a C-section at 800 to 2500 dollars, catching a stall 2 weeks early is the cheapest insurance in the whole litter, and the itemized total sits in the breeding cost calculator.
Five Things to Do This Week
- Weigh her once, same scale, same time, before food, and write the date beside the number.
- Compare against the week column above, not against last week alone.
- Measure abdominal girth at the widest point weekly from week 5, in centimeters.
- If 2 checks land within 20 grams between weeks 5 and 8, book ultrasound within 7 days.
- At day 55 to 60, get a skeleton count on X-ray so you know how many kittens to expect.
Frequently asked
How much weight should a pregnant cat gain in total?
Twenty to thirty percent of her pre-breeding weight across the 9 weeks, which for a 4 kg queen is 800 to 1200 grams. Under 5 percent of that arrives in the first 4 weeks, and 3 to 5 percent per week in the last 2 weeks, because about 70 percent of fetal weight is laid down after day 42.
My queen's weight has not changed for 2 weeks. What now?
Book an ultrasound within 3 to 7 days. A flat scale between weeks 5 and 8 can mean resorption, a mummified fetus, a smaller litter than expected, or simple underfeeding. Add an X-ray skeleton count at day 55 to 60, and check for vulvar discharge, which often accompanies resorption.
How much weight does a queen lose right after giving birth?
Usually 10 to 15 percent within 24 to 48 hours, from kittens, placentas and fetal fluid. A 5.0 kg queen typically lands at 4.35 to 4.50 kg. Do not try to feed the gap back in the first 48 hours, but weigh her at 24 hours and day 7 to confirm she is stable.