As both a veterinarian and breeder mentor, I’m often asked:
“Why Did my Dam Resorb Her Puppies?”
Fetal resorption is more common than most breeders realize. It occurs when an embryo or early fetus dies before the bones have mineralized (usually before day 35 of gestation). The body simply reabsorbs the tissue, often without any outward sign.
Many breeders worry they did something wrong, but often these cases are natural biological safeguards. Still, there are identifiable causes, and understanding them can help prevent future losses.
Key Reasons for Puppy Resorption
1. Embryonic or Genetic Abnormalities (Most Common)
- Random chromosomal errors
- Recessive gene combinations
- Inbreeding depression/high COI
- Structural genetic defects incompatible with life
2. Hormonal Instabilty
- Progesterone is essential for maintaining pregnancy; dips can cause loss
- Causes include:
- Luteal insufficiency (low progesterone)
- Hypothyroidism
- Ovarian cysts
- Split or irregular cycles
- Age-related hormonal decline
3. Infection (Often Subclinical)
- A dam does NOT have to look sick for infection to cause resorption
- Key culprits:
- Brucella canis
- E. coli
- Streptococcus canis
- Mycoplasma/Urea
- Canine herpesvirus (CHV-1)
- Protozoal infections (Neospora, Toxoplasma)
4. Uterine Environment Problems
- Unhealthy uterus impairs implantation and placental development
- Contributors:
- Cystic endometrial hyperplasia (CEH)
- Scarring from past pyometra
- Chronic progesterone exposure
- Previous infections
- Anatomical abnormalities
5. Maternal Health & Stress
- Health and environmental stability are critical
- Factors:
- Obesity (increased inflammation disrupts implantation)
- Fever or systemic illness around implantation
- High stress (travel, boarding, household disruptors, dog fights, pack instability)
- Medications (corticosteroids)
- Toxic exposures
6. Sire Factors
- Poor semen quality and sperm DNA defects cause early embryonic loss
- Suspect issues if several dams bred to the same stud fail:
- Sperm morphology issues
- Semen contamination
- Genetic incompatibility
- Infections transmitted via semen
When Should Breeders Investigate Further?
Consider deeper investigation if:
- Litter sizes drop over time
- Pregnancies vanish between day 25 and day 35
- Multiple dams on the property lose litters
- The same sire is involved in repeated failures
- The dam is overweight or hormonally irregular
Step-By-Step Diagnostic Approach
1. Confirm pregnancy early (to know if resorption occurred)
2. Screen for infection
- Vaginal/uterine culture
- CHV-1 titer
- Brucella test
- Progesterone checks during early pregnancy
- Full thyroid panel
- Ultrasound for CEH or scarring
6. Review health, stress, environment, & medications
Following this framework dramatically increases litter retention.
In a Nutshell
Dams resorb puppies because something disrupted early
embryonic development—most commonly genetics, hormones, infection, or uterine
health. As breeders, our job is to create the conditions where as many embryos
as possible can implant, thrive, and develop into healthy puppies.
Helping breeders achieve this is one of the core pillars of what I teach inside the Elite Breeder Formula program—because once you understand why these losses happen, you gain the power to prevent the majority of them.
About the Author
Dr. Meg Howe is a veterinarian, breeder, mentor, and founder of Elite Breeder Formula.
Additional information from Paula Vandervoort, Senior Breeder, Founder of The Dog Breeder Store LLC.
"If you find that an infection is at play, homeopathics can be very helpful. You can find homeopathic Narayani WAR in our store. It is safe to use during pregnancy, whelping and lactation, and will not cause gut dysbiosis."
Tagged Products
