Puppy absorption in dogs remains a largely unexplored subject. We don't have reproductive veterinarian care anywhere near to us in Rapid City so we've resorted to online searches to answer many questions as to circumstances facing us and our females. Often, pregnancy isn't confirmed before some or all fetuses are reabsorbed. In some cases, the dog owner might not even be aware of the pregnancy! However, breeders frequently deal with this enigmatic phenomenon. While obviously ill dogs might reabsorb their pregnancies, perfectly healthy ones can as well.
The Journal, Theriogenology, in its article titled Embryonic resorption rates at canine pregnancy, notes that resorption rates during the embryonic stage can impact 11-26% of conceptions and 5-43% of all pregnancies.
Sometimes, the cause is clear, but not always. Breeders and pet owners can take measures to prevent puppy absorption, though there's no guaranteed way to stop it completely. Here, we provide all the information you need, including possible causes and complications.
What Will Be Discussed:
What Is Canine Fetal Resorption?
As the term implies, puppy absorption, also known as canine fetal resorption, occurs when the mother reabsorbs an embryo (up to day 25–35, according to various sources) or fetus (after 30–35 days of gestation). By this stage, the puppy has ceased developing and is regarded as deceased.
The puppy's body starts to decompose inside the womb. Enzymes either fully or partially break down the body, allowing the compounds to be reabsorbed into the mother's bloodstream. Alternatively, they may stay in the uterus and be expelled without being noticed.
This process resembles early embryo loss in pregnancy, usually before days 15 to 17. Puppy absorption can occur anytime, typically in the first half of pregnancy. After this, as the fetal skeleton calcifies, the deceased puppy may be stillborn or mummified in the uterus.
Fetal resorption in dogs frequently takes place early in pregnancy and may go unnoticed. Sometimes, the cause is beyond anyone's control. The fetuses affected typically have genetic or structural abnormalities that lead to halted development.
Typically, just one or two puppies in a litter are absorbed, allowing the dog to remain pregnant. The fetus vanishes from the uterus and is reabsorbed into the dog's body. This is different from a miscarriage, where the fetus is expelled.
What Causes Fetal Resorption in Dogs?
Puppy reabsorption has many causes and often goes unnoticed by owners due to its early occurrence in pregnancy, with no outward signs, allowing the female to continue a healthy pregnancy.
Usually, causes fall into two main categories: non-infectious agents and infectious agents.
Non Infectious Causes:
Mal-nutrition: Proper nutrition is essential for fetal development. A lack of necessary nutrients or calories can cause improper development or fetal resorption. We just published an article on this and puppy nutrition. You can read the article here.
Stress: While unproven, maternal stress is suggested to cause pregnancy loss. Stress from unrelated illnesses can lead to reabsorption, but the effect of environmental stress is unclear.
Overcrowding: Too many puppies and not enough nutrients for the mother to carry them all full term.
Trauma: Trauma a mother might encounter during pregnancy, like a car accident, can result in fetal absorption, stillbirth, or miscarriage.
Endocrine Disorder-Hypothyroidism: This condition occurs when a female produces insufficient thyroid hormones. It is debated how much hypothyroidism affects fertility and can lead to abortion, fetal absorption, or stillbirth.
Low Progesterone Levels: Progesterone is essential for pregnancy recognition and maintenance. Low levels can prevent embryos from properly attaching to the uterus, leading to reabsorption, abortion, or complete pregnancy loss.
Uterine Deformities: An improperly formed uterus can hinder fetal development, potentially causing serious infertility issues or, in minor cases, difficulty in fetal development and reabsorption.
Diseases: Unrelated health issues like diabetes and pregnancy toxemia can cause puppy reabsorption. Diabetes, if unmanaged, may lead to fetal reabsorption, while pregnancy toxemia, a serious metabolic disorder from poor nutrition and large litter size, can also be a factor.
Infectious Causes:
Viral Infection: Common canine viruses can affect developing puppies. Canine herpesvirus 1 can cause infertility and pregnancy loss, often without symptoms in females. Canine distemper virus may lead to spontaneous abortion and reabsorption due to illness stress. Canine parvovirus is linked to early puppy reabsorptions and abortion.
Bacterial Infection: Brucella canis can lead to stillbirths, late-term abortions, early embryonic loss, and fetal resorption in dogs. It impacts the reproductive system and may result in lethargy, swollen lymph nodes, and reduced appetite, although some dogs might show no symptoms. It poses a health risk to humans and is a reportable disease in most countries.
The images above show a positive pregnancy scan at 30 days gestation.
Rescan at 7wks and nothing left.
6 puppies absorbed and 1 stillborn mummified
In Closing
Why write this blog? One word comes to mind for the answer: education. Additionally, the "Whelping Room" has been established to give back. The article aims to shed light on an often experienced and complex problem in breeding. After three natural cover breedings with one of our females, we've had only one result in a full-term pregnancy, with unclear reasons initially for the other two failures. This bitch experiences a short heat cycle, which was proven through progesterone testing. This testing also yielded, once it was determined, our first pregnancy. However, following the path leading to the first pregnancy didn't produce a second litter.
With no immediately accessible reproductive veterinarians in our area to attempt to determine a more root-level cause, if there is one, we're still looking for answers. We could seek out a reproductive vet, but most are a minimum of 5 hours away, and even then there's no guarantee we'll find an obvious smoking gun.
Fetal resorption often goes unnoticed by breeders and dog owners unless it occurs late and is detected by an early ultrasound. Many causes are beyond breeder control, with genetic unsoundness being a common reason for the phenomenon.
Fetal absorption can occur early, sometimes before realizing the dog is even pregnant. Illnesses and infections may cause pregnancy loss, with various conditions linked to reduced puppy survival. Viruses can affect fetuses directly, while infections can hinder the mother's ability to maintain a healthy pregnancy.
Puppy reabsorption is generally not a concern unless the mother shows signs of illness or vaginal discharge. If not caused by an identifiable infection, chronic, or underlying condition, it may just be part of breeding.
Cedar Point has discussed this numerous times with our vet and other breed mentors, but has yet to seek out a visit with a reproductive specialist. We are heading in for an ultrasound this coming week with our female who's been challenged with getting pregnant and/or going full term. We have our fingers crossed that this litter has taken, both the female and the pups are healthy, and that by waiting until the third trimester of gestation for the ultrasound, we will know with higher probability whether, one, she's pregnant and two, she's likely to go full term this time again. What's been hard for us is deciding on what's the right thing to do given our situation, and what is best practice. Our journey to this point has been one of constant discovery. We haven't had clear-cut answers to the many questions we've been faced with along her breeding pathway either. It took us nearly three years to vet her for breeding, more to realize that her heat cycle is abbreviated, and it's been difficult to know with certainty how to chart things going forward. Progesterone testing was key, which we haven't typically used with our other breeding females. We have a stud and he's been flawless at highlighting peak estrus for all the girls. Hence the reason we've researched the topic and written this blog.
What do you think, or how would you handle a similar situation? Some details of our journey are lacking in this post; please realize this. It wasn't the intent of the article to tell our story. However, the journey has posed many questions for us starting out with her and our others. If you have suggestions given the limited perspective into our situation and feel compelled to contribute, we ask that you be gentle in your presentation. We also hope there's value in the blog and the personal experience.
On a final and obvious note, we are not veterinarians, or even more specifically reproductive specialists. We are simply Small Munsterlander hunters, developing trainers, a recognized breeder, and aspiring learners. So keep this in mind too. It's been a wonderful journey, one likened to a roller coaster ride at times. Thankfully, we've been blessed with the stomach for it, or we would have bowed out or tossed cookies some time ago. It is not for the faint of heart! The longer we suspect one's been breeding, the more intense the ride realized.
Jeff Mizenko
Cedars Point Kennel
Summerset, SD
425 241-7788
Jeff Mizenko is the owner of Cedars Point Kennel in Summerset, SD. He's a late onset hunter, aspiring trainer, husband, and breeder of Small Munsterlanders. He loves adventure and acquiring life experience.
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