Relaxin In Diagnosis Of Canine And Feline Pregnancy


“Oh, so you’re taking the day off today, Dr. Randolph?”

No, I didn’t say relaxin’, I said relaxin.

Relaxin is a hormone that is produced during pregnancy in mammalian species. Both its function and its importance vary among species, but its main function seems to be to cause a softening and growth of the uterine cervix, at least in rats and pigs. A soft cervix allows easier delivery, especially in species which usually have multiple young at each delivery.

Our interest in relaxin, today, is its use in dog and cat pregnancy diagnosis. Relaxin is produced in sufficient amounts in canine and feline pregnancy that, after 27-30 days of pregnancy your pet’s doctor can obtain a blood sample, submit it to a laboratory (or perform the test in his office) and let you know whether your pet is actually pregnant or is experiencing a false pregnancy.

False pregnancy is rarely a problem in cats, but dogs experience all of the physical and visual aspects of pregnancy when the relationship of estrogen and progesterone mimic the changes that occur in real pregnancy.

So, if your dog begins nesting, has swollen mammary glands and is looking bigger in the abdomen, you can know whether to build a whelping box.  Or not.

Dogs with repeated false pregnancies, also called pseudopregnancy, should be spayed because of their tendency to fill the uterus with fluid, resulting in a uterine infection called pyometra.

If you think your pet may be pregnant, schedule an appointment with your veterinarian.

Now that I’ve written today’s post, it might just be a good time for a little relaxin’.

See you tomorrow, Dr. Randolph.

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