Most catteries lose a litter to something a scale would have caught 10 to 14 days earlier. A pregnant queen should gain 25 to 40 percent of her pre-mating weight between day 0 and day 63 to 65, weighed on a fixed schedule: every 4 weeks through mid-pregnancy, then every 7 days. Exactly 2 warning signs justify a same-day vet call — a flat or falling weight across 2 consecutive checks, and a single week above 7 percent. A queen carrying 1 kitten usually finishes under 10 percent total gain, and that is the third number worth knowing before the first mating.
Four Numbers on One Log Sheet
The whole system is 4 fields in a single column: baseline weight on day 0, gain in grams since the last check, cumulative percent against baseline, and days since mating. Read together, those 4 numbers let a vet rebuild a pregnancy over the phone in about 2 minutes. Read alone, any one of them misleads.
Typical baselines run 2.8 kg to 4.5 kg depending on breed. At that size, a 100 g error at day 0 shifts every later percentage by roughly 2.5 to 3.5 points, enough to hide a real stall of 2 weeks. Use one digital scale, on a hard floor, never on carpet, and keep the same scale for the whole pregnancy.
Baseline: Three Mornings Before Mating
Weigh the queen on 3 consecutive mornings before mating and keep the average, rounded to the nearest 10 g. Do it before the first meal, after the litter box, in the same room, on the same folded towel. A queen who fights the scale can be weighed inside a carrier: carrier alone first, then carrier plus cat, then subtract. The two methods agree within about 20 g when the cat is calm, and 20 g of noise does not matter when the signals you are hunting are 200 g or larger.
Log the weight on the same sheet as the mating date. A cattery that records weight but not the mating date cannot compute days, and days decide whether a plateau at week 4 is normal or 10 days overdue.
The Week-by-Week Schedule
From day 0 to week 4 there is little to see. Most queens gain 0 to 8 percent, and some gain nothing because the fetuses are small and appetite has not risen yet. A 4-week interval is enough at this stage. From week 5 the curve steepens, and from week 7 a 7-day interval is the minimum that catches trouble while there is still time to act on it.
| Stage | Days after mating | Expected gain vs baseline | Weighing interval |
|---|---|---|---|
| Baseline | 0 | 0 percent | 3 mornings, average |
| Early | 1 to 35 | 0 to 8 percent | every 28 days |
| Mid | 36 to 45 | 10 to 20 percent | every 14 days |
| Late | 46 to 55 | 18 to 30 percent | every 7 days |
| Final week | 56 to 65 | 25 to 40 percent | every 3 to 4 days |
Two weighings close together beat one perfect weighing. A single reading of 3.9 kg says nothing without the 3.7 kg from 7 days earlier, and the 200 g difference is the entire message.
Why 25 to 40 Percent Is the Target
The gain is not fat. A litter of 4 kittens at 90 to 115 g each accounts for roughly 360 to 460 g at birth, plus 100 to 150 g of placenta and membranes, plus amniotic fluid and uterine growth in the 300 to 500 g range. On a 3.5 kg queen that lands at 0.8 to 1.1 kg, or 23 to 31 percent — inside the band with room to spare.
Litters of 6 or 7 push the top of the range toward 40 percent and occasionally past it. A thin queen often gains 35 to 40 percent and finishes healthy; an overweight queen may finish at 25 percent with a normal litter of 3. Judge the curve against the queen you started with, not against the cattery average.
Warning 1: Flat or Falling Across Two Checks
A drop of 100 g or more between 2 checks, or 2 checks in a row with zero gain after week 5, is the first alarm. Before week 5 a plateau is common and usually means nothing. After week 5 it can mean resorption, an empty uterus, or a queen who is not taking in enough to support the litter.
The next step is ultrasound, which confirms heartbeat and fetal number from about day 21 to 25 and is worth repeating at day 40 to 45 if the curve stays flat. X-ray counts skeletons more reliably from day 55 onward, and 2 views at that stage usually give a litter count accurate to within 1 kitten.
Warning 2: More Than 7 Percent in Seven Days
The second alarm is speed. A gain above 7 percent of body weight in 7 days, held across 2 readings, or a cumulative gain above 40 percent before day 60, deserves a call. Large litters do this legitimately, but so do fluid accumulation and a single kitten that has grown unusually large.
Do not cut food to flatten the curve. Restricting a pregnant queen pushes birth weights down, and 85 to 110 g is already the low end for most breeds. Change the schedule instead: move to a 3-day interval, photograph the log, and let the vet interpret the numbers with the ultrasound in hand.
Single Kitten: When Gain Stays Under 10 Percent
A litter of 1 is the most common reason a queen finishes at 5 to 9 percent. One kitten at 100 g plus placenta and fluid gives roughly 250 to 350 g on a 3.2 kg queen, or 8 to 11 percent. That is not a failure, it is arithmetic.
Single-kitten pregnancies still need attention. The kitten can grow large enough to make delivery difficult, labor may start late, and the queen may skip obvious nesting behavior. Book a check at day 40 to 45 and again at day 58 to 60, and keep a clinic number reachable on day 63, because 1 kitten labors are the ones most likely to need help at 2 a.m.
What to Do With the Sheet
- Weigh on day 0, day 28, day 42, then every 7 days from day 49 until delivery, and once within 24 hours after birth to set the post-whelp baseline.
- Record to the nearest 10 g, and write appetite and litter box notes in the next column.
- Flag 3 things: any single week above 7 percent, any 2-check flat line after week 5, any total under 10 percent at day 56.
- Photograph the sheet every 7 days so a phone copy settles date questions later.
- When you call, give the days-since-mating figure first, then the last 3 weights.
The wider protocol for a normal pregnancy sits in our guide to queen pregnancy weight gain, and planning a queen's exit from the program belongs with breeding queen retirement. This schedule implies 2 to 3 clinic visits, so price them before mating rather than after; the cost tools page breaks visits down by region.
Frequently asked
How often should I weigh a pregnant queen?
Weigh her on day 0, again at about day 28 and day 42, then every 7 days from day 49 until she delivers, and once more within 24 hours after birth. A 4-week interval fits the first half of pregnancy, when most queens gain only 0 to 8 percent; from week 7 a 7-day interval is the minimum that still leaves time to act.
Is a 25 to 40 percent weight gain really normal?
For a 3.5 kg queen carrying 4 kittens, the kittens, placentas, fluid and uterine growth add up to roughly 0.8 to 1.1 kg, which is 23 to 31 percent. Litters of 6 or 7 push the figure toward 40 percent. A queen that starts thin often lands at 35 to 40 percent, and an overweight queen may finish near 25 percent with a normal litter.
What should I do if the weight stops rising?
Two checks in a row with no gain after week 5, or a drop of 100 g or more, warrants a call. Expect an ultrasound around day 21 to 25 to confirm heartbeats, repeated at day 40 to 45 if the curve stays flat. From day 55 an X-ray with 2 views usually counts the litter to within 1 kitten.