Premature Labor in Dogs

Last updated: Oct 28, 2020

Some females can develop preterm labor. This is when she goes into labor prior to 61 days of pregnancy, based on ovulation timing with progesterone tests. Unlike human pregnancies, dog and cat pregnancies are a short 63 days long. Puppies or kittens not delivered within a 48-hour window of 63 days from ovulation are at a greatly increased risk of death. When born more than 48 hours in advance of the due date, their lungs are underdeveloped and they cannot breathe. If born at this stage, they often are born without hair on their faces. When born more than 48 hours after their due date, their placentas have frequently become dysfunctional. Here, the puppies or kittens fail to survive due to a lack of blood flow and oxygen that should have been delivered to them through their placentas.

This is why careful timing of the ovulation date is essential. Even if you are successful in getting your girls pregnant, getting them "unpregnant" at the right time is critical to their survival.

Causes of Premature Labor in Dogs

Causes of preterm labor can be divided into two categories:

1. Primary hypoluteoidism - this is caused by the female not producing enough progesterone from her ovaries. This may be an inherited condition so be aware of this before you plan to keep a female puppy from her for your breeding program.


2. Secondary hypoluteoidism - this is caused by having something wrong with the puppies or female and her body trying to eliminate the pregnancy. The reasons for this can include genetic incompatibility between the sire and dam, infectious causes such as canine herpesvirus, canine brucellosis, trauma, stress, and many other reasons.

To safely treat the dam for preterm labor, you must know that the puppies still have heartbeats, based on abdominal ultrasound. Perpetuating a pregnancy with deceased pups in the uterus is never a healthy situation for the female. If the pups are all deceased, you need to plan to let her miscarry the pups or have a veterinary intervention to allow her to clear them out of her uterus.

Signs of Premature Labor in Dogs

Signs of impending preterm labor include nesting, lactation, loss of appetite, vomiting, and any vaginal discharge that is not clear. Intervention may be successful at this time if initiated promptly.

Sometimes, there is no warning and you just find an underdeveloped puppy or kitten delivered. By this time, it is often too late to interrupt her labor and save her litter.

Intervention Options

If preterm labor is suspected, immediate veterinary intervention is essential. An abdominal ultrasound to assess for fetuses with actively beating hearts and a progesterone test is required. If the progesterone is below 3 ng/ml, and she has live fetuses, there are several interventions that can start.

1. Terbutaline - either oral or injectable: Helps relax and quiet her uterus. This is a human asthma medication and is frequently available at a local pharmacy. This can be started at any time during the pregnancy, but often the female becomes resistant to it during its use, requiring increasingly high doses to be administered.


2. Antibiotics: Be sure to use one that is safe during pregnancy such as Clavamox. This should be started for two reasons. First, it can help manage a septic pregnancy, one where bacteria are affecting the health of the puppies, and help save their lives. Second, when the cervix is open as it will be during preterm labor, antibiotics will protect the mother from ascending bacterial disease. Avoid trimethoprim/sulfa and other antibiotics that can cause birth defects in the puppies. Use amoxicillin or other safe antibiotics that can be initiated at any time during the pregnancy.


3. Fenbendazole: A dewormer should be initiated at a daily dose of 50 mg/kg. This is used in the event that the cause of her preterm labor is parasite migration of roundworms through the uterine wall into the placentas, disrupting the placental attachments. This can be started at any time during the pregnancy.


4. Progesterone: The hormone of pregnancy. There are oral and injectable forms of progesterone. The oral form is an equine product, the injectable form needs to be compounded in oil. This should NOT be started before day 45 of the pregnancy. Initiation of treatment earlier will lead to the development of abnormal genitals of the pups, producing intersex puppies (pups that have neither male nor female genitals.) This should only be used if low progesterone can be demonstrated on a blood progesterone test on the female. Using it inappropriately will lead to trouble.

When using terbutaline and/or progesterone to support a pregnancy, you MUST know her due date. Because both drugs will delay the onset of normal labor, indiscriminate or inappropriate use will lead to extended pregnancy length. This will lead to the loss of the litter if the drugs are not stopped at the appropriate time to allow natural labor to occur. If used too long, a c-section to intervene will be required. There are no drugs available in the U. S. at this time that can initiate labor.

Additionally, progesterone administration will suppress lactation. This must be managed if she is going to be able to lactate and produce colostrum for her pups when they are ready to nurse. Supplemental feeding of formula without the mom's colostrum can lead to inadequate immunity passed to her pups.

In Summary

In summary, to safely perpetuate a pregnancy with preterm labor you must have:

1. Live puppies based on ultrasound. (Do not interchange with viable as this implies the ability to survive outside the uterus.)
2. A precise known due date based on ovulation timing with progesterone testing.
3. A diagnosis from your veterinarian of the reason for her preterm labor to allow for specific treatment.
4. Prescription medications from your veterinarian to manage the specific condition your dog or cat is experiencing. This likely will require multiple medications.
5. Supplementation of metoclopramide and Breeder's Edge Oxy Momma prior to whelping to assure your female will lactate once the puppies are born.
6. A lot of good luck while planning to not get much sleep.

If you have more questions on canine pregnancy, call a Revival Pet Care Pro at 800.786.4751.

-Dr. Greer
Marty Greer, Doctor of Veterinary Medicine, Director of Veterinary Services at Revival Animal Health

Marty Greer, Doctor of Veterinary Medicine, has 35+ years' experience in veterinary medicine, with special interests in canine reproduction and pediatrics. She received her Doctor of Veterinary Medicine from Iowa State University in 1981. She's served as Revival's Director of Veterinary Services since 2019.