Calcium is an essential component of the skeleton, and it has important functions in muscle contraction, blood clotting, enzyme activity, the nervous system, and hormone release, among others. Many different metabolic disorders affect calcium metabolism and can lead to abnormally high or low levels of calcium in the blood (see Hormonal Disorders of Cats: Disorders of the Parathyroid Glands and of Calcium Metabolism in Cats).

In cats, a disorder of calcium metabolism known as puerperal hypocalcemia may occur 2 to 3 weeks after giving birth, when the mammary glands are producing the greatest amount of milk. Other names for this condition include postpartum hypocalcemia, periparturient hypocalcemia, puerperal tetany, and eclampsia. This life-threatening condition is less common in cats than in dogs. Low levels of calcium in the blood can cause seizures. Early signs include listlessness, restlessness, and lack of appetite. The queen may be unwilling to let kittens nurse.

A tentative diagnosis is based on the history, physical examination, clinical signs, and response to treatment. A blood test to determine the level of calcium confirms the diagnosis.

Immediate veterinary medical treatment is needed for cats with puerperal hypocalcemia. Calcium solutions given intravenously usually result in improvement within 15 minutes. Kittens should not be allowed to nurse for 12 to 24 hours. During this period, they should be fed a milk substitute or other appropriate diet. After the acute crisis, calcium supplements are given for the rest of the lactation. Vitamin D supplements also may be used to increase calcium absorption from the intestines.

Last full review/revision July 2011 by George M. Barrington, DVM, PhD, DACVIM; David L. Evans, BVSc, PhD; Don A. Franco, DVM, MPH, DACVPM; Katharine F. Lunn, BVMS, MS, PhD, MRCVS, DACVIM; Donald C. Sawyer, DVM, PhD; Jean A. Hall, DVM, PhD, DACVIM; Sharon J. Spier, DVM, PhD, DACVIM; Ivan W. Caple, BVSc, PhD, MACVSc, MRCVS