Eclampsia (Milk Fever) in Dogs – Causes, Signs & Prevention

What every breeder should know about calcium balance, prevention, and early intervention.

Eclampsia, also known as Milk Fever or Puerperal Tetany, is a potentially fatal condition seen in lactating dogs. It occurs when calcium levels in the blood drop dangerously low during the peri-parturient period — the time shortly before, during, or after whelping. Although most cases develop within 1–4 weeks after birth, it can also occur late in pregnancy or even before labour begins.

Understanding Calcium Regulation in Dogs

Calcium plays a vital role in muscle contraction, nerve transmission, and many body functions.

Too little calcium (hypocalcaemia) leads to muscle tremors, seizures, and abnormal neurological activity, while too much can cause tissue calcification and organ failure.

The balance is maintained by two hormones:

Parathyroid hormone (PTH) – increases blood calcium by drawing calcium from bones, improving intestinal absorption, and reducing calcium loss through the kidneys.
Calcitonin – produced by the thyroid gland, acts as a counterbalance to lower blood calcium.

When this balance is disrupted — especially during lactation, when calcium is lost through milk — eclampsia can develop.

Causes of Eclampsia

Several factors can lead to calcium depletion:

Increased calcium loss or demand
- Milk production during lactation rapidly depletes calcium stores.
- Foetal bone formation during pregnancy uses significant amounts of calcium.
Reduced calcium intake
- Decreased appetite in late pregnancy or early lactation reduces calcium intake.
Suppressed parathyroid response
- Over-supplementation of calcium during pregnancy suppresses PTH release, weakening the body’s ability to mobilise calcium when it’s needed most.
Stress and hyperventilation
- Panting or stress during labour can cause calcium to bind to proteins, reducing the amount of free calcium in the blood.

Who’s Most at Risk?

Eclampsia can occur in any breed, but is most common in:

Small or toy breeds (Chihuahuas, Pomeranians, Maltese)
First-time mothers
Dams with large litters
Dogs with a history of calcium imbalance
Bitches over-supplemented with calcium during pregnancy

Recognising the Signs

Early detection is key to saving the dam’s life.

Symptoms usually appear suddenly and can progress rapidly.

Early symptoms:

Restlessness, pacing, or anxiety
Poor mothering or disinterest in pups
Excessive panting or whining
Facial itching or pawing at the face
Stiff or uncoordinated gait
Muscle twitching or trembling
Warm ears or fever
Vomiting or diarrhoea

Severe symptoms:

Body stiffness (tetany)
Seizures or convulsions
Collapse or coma
Rapid, heavy breathing and dilated pupils

Without immediate treatment, eclampsia can become fatal within hours.

Diagnosis

Veterinarians diagnose eclampsia based on:

Clinical signs and recent whelping history
Response to calcium infusion
Blood tests confirming low calcium, and occasionally low glucose or magnesium

Emergency Treatment

Eclampsia is a true emergency requiring veterinary care.

Treatment typically includes:

Intravenous calcium gluconate (10%) – given slowly (0.5–1 mL/kg) while monitoring the heart with ECG.

Rapid infusion can cause dangerous arrhythmias, so calcium is administered under close supervision.
Temperature control – use cool, damp towels or alcohol rubs on groin and armpits to manage fever.
Fluid therapy – IV fluids to correct dehydration or shock.
Glucose support – hypoglycaemia may accompany hypocalcaemia and must be corrected.
Oral calcium supplementation – after stabilisation, the bitch may continue on oral calcium gluconate tablets (10 mg/kg two to three times daily) during lactation.

Puppies are often temporarily removed until the dam recovers and her calcium levels stabilise.

Prevention for Breeders

Prevention begins during pregnancy and continues through lactation:

✅ Balanced Nutrition

Feed a high-quality breeder diet designed for pregnancy and lactation. Avoid routine calcium supplements before whelping unless prescribed by your vet — premature supplementation can suppress natural calcium regulation.

✅ Post-Whelping Support

Begin oral calcium supplementation after whelping, particularly in small breeds or large litters. (We also recommend calcium supplementation DURING whelping, but for a different reason; Dystocia). Suitable options include:

✅ Monitor Daily

Take the dam’s temperature twice daily using a Digital Thermometer (Fast, Flexible) and observe for behavioural or neurological changes.

✅ Manage Litter Demand

For large litters, rotate feeding or hand-rear some puppies using a quality Puppy Milk Replacer to reduce strain on the dam.

When to Call Your Vet

Seek immediate veterinary attention if:

Your dam becomes restless, trembles, or pants heavily without heat.
She suddenly refuses to nurse.
Her body temperature exceeds 40.5 °C.
She experiences stiffness or seizures.

Quick intervention saves lives — most dogs recover fully if treated early.

Final Thoughts

Eclampsia can develop suddenly, but with good nutrition, careful monitoring, and timely veterinary care, it’s largely preventable. Breeders who stay vigilant during the postpartum period give both dam and pups the best chance for a healthy start.