Eclampsia, the acute drop in blood calcium that hits nursing queens, appears 2 to 4 weeks after birth in most cases, peaks around day 21, and can kill a queen within hours. The first signs are easy to dismiss: restlessness, panting, a stiff gait, ears twitching. Within 1 to 2 hours she can be in tonic-clonic seizures with a temperature above 40 Celsius, and by then it is an emergency, not a wait-and-see.

What is actually happening

Milk production pulls 30 to 50 mg of calcium per deciliter of milk out of the queen's blood every day. If dietary calcium and bone reserves cannot keep up, serum ionized calcium falls below roughly 0.8 mmol/L, and nerves fire without a threshold. That is why the signs are neuromuscular first, and why a queen on a good diet can still crash when she is nursing five kittens.

Large litters, first-time queens, small breeds, and queens fed a high-phosphorus or all-meat diet are at highest risk. The peak milk demand sits in weeks 2 to 4, exactly when the signs appear.

The 2 to 4 week window

Most cases present between day 14 and day 28, with day 18 to 24 the busiest. Queens that lose a litter and are re-bred on the next heat cycle, or that foster an extra litter on top of their own, can present earlier. After week 5, demand falls as kittens begin to eat solids, and the risk drops sharply.

Track it: write the kindling date on the box and check the queen's gait and breathing daily from day 10 to day 35. A queen that will not jump onto the nest box, or stands with her hind legs stiff, is the earliest finding, often 12 to 24 hours before a seizure.

Signs, and the temperature trap

Early: pacing, panting without heat, fine muscle tremors in the face and ears, a stiff-legged walk, hypersensitivity to sound or touch. Late: rigid limbs, paddling, seizures, and a temperature that can reach 41 Celsius.

Ask what changed in the last 12 hours. Queens rarely show one isolated sign; the pattern runs restlessness at night, refusal to lie down, a stiff walk, then open-mouth panting. A queen that was nursing well and suddenly pushes the kittens away is showing the same thing a day earlier.

The temperature trap is treating that fever with cold water or ice packs. The rise comes from muscle activity, not infection, and cooling a seizuring queen worsens the calcium crisis and risks hypothermia once the seizure stops. Never give an anticonvulsant or a sedative at home either; the seizure is a calcium problem, not an epilepsy problem.

Calcium: the dose the vet will use

Definitive treatment is 10 percent calcium gluconate at 0.5 to 1.5 ml/kg, given slowly intravenously over 10 to 15 minutes while listening to the heart. Slow is the whole point: calcium given fast causes bradycardia and arrhythmia, which is why this is a veterinary procedure with ECG or auscultation, not an at-home injection.

Many queens respond within 5 to 10 minutes, relax, and stop seizing. If seizures persist, a second dose at half the first can be given after 15 minutes, and diazepam 0.5 mg/kg intravenously is used for seizure control while calcium takes effect. Oral calcium carbonate 1 to 2 g per day follows once the queen is stable, split into 2 doses.

What to do in the car

  • Call the clinic and say the words nursing queen with seizures so they prepare calcium.
  • Wrap her in a towel, keep the car at 22 to 24 Celsius, avoid direct heat.
  • Keep the head slightly raised and the airway clear of saliva.
  • Bring the kittens in a box; they may need to be separated for 12 to 24 hours.
  • Do not put anything in her mouth during a seizure.

After the crisis: diet and weaning

Remove the kittens for 12 to 24 hours and feed them milk replacer by bottle, which immediately cuts the calcium drain. Then either wean fully at 5 to 6 weeks, or allow short supervised nursing 3 to 4 times a day while supplementing the kittens with gruel from week 4.

Watch her for 48 hours after the first dose. Recurrence is common when full nursing resumes inside 24 hours, which is why the kittens stay off for at least a day and go back gradually. A queen that trembles again after going home needs a repeat injection, not a second opinion.

Feed a growth or lactation diet with a calcium-to-phosphorus ratio near 1.2 to 1 and 1.2 to 1.6 percent calcium on a dry matter basis. Do not add extra calcium during pregnancy: over-supplementation suppresses the queen's own parathyroid response and makes eclampsia more likely, not less. Save supplementation for lactation, under veterinary direction.

Keeping the kittens fed while she recovers

Kittens under 3 weeks need milk replacer 8 times a day, older ones 6 times, warmed to 38 Celsius: 4 to 6 ml per feed at 200 g and 8 to 11 ml at 280 g. Hold the box at 30 to 32 Celsius, because a chilled kitten stops digesting and milk then sits in the gut. Weigh daily before the first feed, and treat a gain under 7 g as a shortfall.

Preventing it in the next litter

Plan the next mating with the stud's owner at least 2 weeks ahead and keep the dates the way stud management records do, so a repeat episode can be predicted at the same point in lactation. Age matters too: check where the queen sits on the cat age chart before committing her to a second litter in the same year.

  1. Feed a complete growth diet from mating onward; no all-meat or homemade meals.
  2. Never supplement calcium in the last 4 weeks of pregnancy.
  3. From week 2 of lactation, offer 1.5 times the normal adult intake in 4 small meals.
  4. Plan weaning to start at 4 weeks and finish by 6, especially in litters over 4 kittens.
  5. If a queen has had eclampsia once, have calcium gluconate on hand and a vet on call for the next litter.

Frequently asked

When does eclampsia usually appear in a cat?

Between 2 and 4 weeks after birth, with day 18 to 24 the peak. Milk production is highest in that window, so calcium demand outruns supply. Signs before week 2 or after week 5 are unusual and should prompt a look for another cause such as hypoparathyroidism, kidney disease, or a poor diet.

Can I treat a seizuring queen at home?

No. The seizure is caused by low ionized calcium, so sedatives and anticonvulsants do not fix it, and cooling the fever with ice makes the crisis worse. Wrap her, keep her warm but not hot, clear the airway, call the clinic, and bring the kittens. Treatment is intravenous calcium gluconate given slowly under cardiac monitoring.

How do I prevent eclampsia in the next litter?

Feed a complete growth diet from mating onward, and do not supplement calcium during the last 4 weeks of pregnancy, because excess calcium suppresses the queen's parathyroid response. During lactation raise intake to about 1.5 times maintenance in four small meals, and wean between 4 and 6 weeks, especially in litters of more than four kittens.