Fetal mummification is an uncommon but critical reproductive illness seen in domestic animals, particularly in cattle, pigs, goats, and rarely horses and dogs. It includes the fetal death during pregnancy with subsequent drying out of the fetus without bacterial putrefaction, while still maintained within the uterus. The disease usually remains unnoticed until normal reproductive checkups identify the presence of a mummified fetus.
What is Fetal Mummification?
Fetal mummification happens when a fetus dies following ossification (development of bone) but before expulsion, and rather than decomposing (like fetal maceration), it dehydrates. The outcome is a dehydrated, shrunken, and firm fetal mass that can remain in the uterus for weeks, months, or years if left undetected and untreated.
Key Characteristics:
- Happens in utero following fetal death
- No bacterial infection is present
- Amniotic and allantoic fluids are reabsorbed
- Fetal tissues dry out and become hard and leathery
Causes and Risk Factors
Some factors can result in fetal mummification, such as:
- Genetic defects or chromosomal anomalies
- Infectious agents such as porcine parvovirus (in pigs), BVD virus (in cattle), or toxoplasmosis (in small ruminants)
- Hormonal imbalance
- Twinning, particularly if one twin is dead and disrupts the expulsion of the other
- Abnormalities in the uterus or inadequate uterine tone
- The specific cause cannot be identified, especially with spontaneous cases.
Types of Fetal Mummification
Fetal mummification is generally divided according to the species or cause:
1. Hematic Mummification (Cattle)
- Most frequently occurring in dairy cows
- It is characterized by a dark chocolate-colored, thick, viscous substance surrounding the fetus
- Most commonly due to twin pregnancy and loss of one fetus
2. Papyraceous Mummification
- Common to several species, but particularly in pigs and dogs
- The fetus is flattened and parchment-like in appearance
- Typically is located in a litter of otherwise healthy fetuses
3. Infectious Mummification
- Usually related to viral or protozoal infection
- More frequent in pigs with pathogens such as porcine parvovirus or PRRSV
Clinical Signs and Diagnosis
Fetal mummification is usually clinically silent. There might be no clinical signs of disease in the dam. Some evidence includes:
- Failure to calve or give birth on time
- No progression of signs of pregnancy
- Irregular return to estrus
Diagnosis:
- Rectal or ultrasound examination (in large animals) to detect a firm, non-viable fetus
- Radiography (in small animals) to detect fetal bones
- Hormone testing, especially progesterone, to determine continuing pregnancy
Management and Treatment
The treatment objective is the removal of the mummified fetus with maintenance of future reproductive viability of the dam.
Medical Management:
- Administration of prostaglandins (PGF2α) to cause luteolysis and uterine contractions
- May involve serial dosing in instances of compromised uterine tone
Surgical or Manual Removal:
Manual or surgical removal (e.g., cesarean section) in some instances, particularly if the cervix fails to dilate
Aftercare:
- Monitor for endometritis or retained fetal membranes
- Initiate supportive therapy and antibiotics as necessary
- Consider the underlying infectious or anatomical etiology
Prognosis
- Excellent prognosis for future fertility if promptly and properly treated
- In multiparous animals (such as swine or dogs), the remaining fetuses can still develop normally
- Recurrence is rare but can occur in genetically susceptible animals
Prevention
Although not always avoidable, certain measures can be taken to minimize the risk:
- Establish biosecurity and vaccination measures (particularly in swine herds)
- Perform routine reproductive health examinations
- Don’t breed animals with established genetic abnormalities or uterine defects
Fetal Mummification (FAQs)
Fetal mummification is a condition in which a fetus dies in the uterus after developing bones (ossification) but is not expelled. Instead, the body becomes dehydrated, shriveled, and preserved in a dry, leathery form without signs of decomposition.
Yes. A veterinarian is essential for accurate diagnosis, safe treatment, and ensuring the reproductive tract is healthy afterward.
In species like pigs and dogs, other fetuses may still develop normally. The mummified fetus may be expelled at birth or remain unnoticed.
Prevention isn’t always possible, but you can reduce risk by:
Maintaining a vaccination program
Practicing good herd/flock health management
Conducting regular reproductive exams
Avoiding inbreeding or using genetically sound breeding stock
Yes, in most cases, the dam can conceive again with proper treatment and no underlying chronic reproductive issues.
Conclusion
Fetal mummification, while rare, is a condition with which veterinarians and cattle producers must be familiar, particularly in the high-reproductive-rate species. Prompt diagnosis and management are critical to the resolution and maintenance of fertility. Knowledge of possible causes, clinical presentation, and treatment alternatives can significantly enhance dam and subsequent pregnancy outcomes.
