Table of Contents

Fetal Mummification in Animals

Fetal Mummification is the death of the fetus at middle of the gestation or at the last third of gestation period which leads to the autolytic changes without putrefaction, abortion of fetal and placental fluids with involution of maternal placenta.

Fetal mummification does not occur in the first trimester of gestation because embryonic or fetal death prior to the development of fetal bones follows fetal resorption and absorption of placental tissues.

The cause for fetal mummification is difficult to rule out as the time of fetal death is not known and autolysis and mummification of the fetus and fetal membranes makes determination of the causative agent not possible.

Fetal mummification is commonly found in cattle and pigs than sheep, horses, dogs and cats.

Etiology

Bovines

The general cause for bovine fetal mummification include torsion of the umbilical cord or compression of the umbilical cord passing around the fetal extremity leading to fetal death. Genetic factors involved are due to inherited endocrine defects and autosomal recessive genes (Common in Jersey Breed).

There is evidence that fetal mummification may follow infectious causes of fetal death such as campylobacter fetus, moulds, leptospira spp and BVD.

Swines

Many viruses like Porcine parovirus, porcine enterovirus, Japanese B Encephalitis and SMEDI etc. can cross maternal placenta and kill the conceptus.

Dead embryos are usually absorbed without a trace, whereas after 30 days of gestational age when skeletal development begins, will either mummified or aborted Uterine overcrowding and placental insufficiency.

Ewe

Fetal mummification is generally found with twins or triplets when one of the embryos has died due to infections like epizootic abortion, Listeriosis, Toxoplasmosis and Leptospirosis with prolonged gestation.

Mare

Mummification is rare and always associated with twins due to lack of placental area. If twinning occurs, one of the foetuses usually develops more slowly than the other. The smaller fetus usually dies. The dead fetus will be mummified and delivered at term along with live foal.

Bitch

Fetal mummifications is characteristic of canine herpes virus infection and uterine overcrowding.

Queen

Not uncommon in cats and is due to uterine overcrowding.
Failure of oestrum.
Not suspected until late in gestation when normal development of the fetus, body changes related to parturition and calving fail to occur.
Mummy remains in semi-moist state without odour or pus until spontaneous abortion in 1-2 months to 1-2 years, or until diagnosed, treated or corrected or slaughtered.

Rectal examination reveals:

Persistent corpus luteum (PCL).
Uterine walls contracted and tightly enclose the conceptus.
Uterine walls fairly thick.
Absence of fetal fluids.
Absence of cotyledons, and
Uterine artery small and absence of fremitus.
In early case
- Uterus feels doughy due to large, soft blood clot.
- Difficult to palpate the fetus.
In long standing case
- Dry, firm and more leather-like fetus (In cow).

Vaginal examination reveals a closed cervix with a mucous seal of pregnancy.

Types of Mummification

There are two types of fetal mummification in domestic animals, they are:

Hematic type
Papyraceous type

Hematic type

The hematic type is most commonly noticed in cattle in which the maternal placenta or caruncle undergoes involution with a variable amount of hemorrhage occurring between the endometrium and fetal membranes which after the placenta has been absorbed leaves a reddish brown, gummy, tenacious mass of autolyzed red cells, clots and mucus imparting a reddish brown colour to the fetal membranes and fetus.

The similarity between the tenacious sticky reddish mucus around the membrane and bovine mummified fetus is striking in this hematic type of mummification.

Papyraceous type

Papyraceous type of mummy occurs in other species and not characterized by placental hemorrhage and hence, the fetus is usually a brownish colour and fetal membranes are not covered with reddish brown tenacious material.

Mummification of Bovine Fetus

Mummification of bovine fetus occurs in cattle at all ages and breeds during the third to eighth month of gestation most commonly in the fourth, fifth and sixth months. If the condition is undiagnosed the mummified fetus will remain in the uterus beyond the normal gestation period. No premonitory signs are observed before the abortion of a mummified fetus and spontaneous abortions are sometimes common.

Fetal mummification associated with a persistent corpus luteum is observed mainly in cattle. Torsion of uterus, umbilicus and trauma are considered to be causes for fetal mummification. Wound infection type organisms and Brucella organisms causing fetal death are not followed by fetal mummification.

Almost all mummified foetuses and uteri when examined and cultured are sterile and free of organisms and the endometrium gets involved and normal conception occurs in the first or second estrus after explusion of mummified fetus.

As the fetus mummifies the uterine walls contract and tightly enclose the conceptus leaving a firmer, dryer leather like tissue with thick uterine wall without cotyledon that can be felt by rectal palpation.

Fetal mummification is characterized by failure of estrum with a persistent corpus luteum without any signs of parturition even after the normal length of gestation.

The mummified fetus does not give any signal for onset of parturition (normally mature fetus at the end of gestation give signal through hypothalamus-pituitary-adrenal axis for onset of parturition). So corpous luteum remains present and also mummified fetus remains present in the uterus for indefinite time (prolonged gestation).

Abnormal cervical seal may be present with the uterus placed in abdomen because of the fetal weight.

The bovine fetal mummy remains in the semi moist state without odour or pus until the condition is diagnosed, treated and corrected even upto two years or unless and until examined for prolonged gestation; while in other domestic animals mummified fetus usually remain in uterus only as long as pregnancy is maintained by other viable fetus and expelled with normal fetus at the time of parturition.

Treatment

Any drug which brings about contraction of uterine muscles, relaxation of cervix, involution or regression of corpus luteum and expulsion of fetus will be the drugs of choice. Hence induction of abortion by luteolysis using prostaglandins or stimulation of uterus with estrogens can be tried with the fetus getting expelled in 2-4 days.

Administration of corticosteroids and manual stimulation of uterus and dilation of cervix will be no use and not advisable.

Prostaglandin Injections

Administration of PGF_2α causes regression of CL. After regression of CL, new follicles develop and cow comes to heat, the cervix opens and the mummified fetus comes out of the uterus and usually lodges in vagina (PGF_2α – Lutalyse, Vetmate, Iliren, Dinofertin etc.,)

By Intra-muscular route:

Cattle: 25 mg (total dose)
Pig: 10 mg
Sheep & Goat: 6–8 mg
Dog & Cats: 0.25–0.5 mg/kg s/cly
Mare: 1.5–2.5 mg BID for 2–4 days (natural) 250–1000 mg i/m (synthetic).

Estrogens (Stilbesterol, Progynon, etc.)

Administration of estrogen causes contraction of uterine muscles and relaxation of cervix, regression of CL and expulsion of fetus. Repeated injections at 48 hours may be necessary.

Total dose-50 to 80 mg of synthetic estrogens or 5 to 8 mg of estradiol (potent drug) by Intramuscular route.

Whether PGF_2α or estrogens are used, expulsion of the mummified fetus may not be complete because of poor dilatation and dryness of the cervix and birth canal. Lubrication of the birth canal and traction are required for the delivery of the mummififed fetus in some cases.

Since there is sterile environment of the uterus, there is no need of antibiotic therapy. If manual traction is applied there may be chance of entry of infection, then antibiotic should be recommended.

After expulsion of mummified fetus, Vitamin A and phosphorous injections should be recommended to restore the uterine epithelial cells for increasing the tone of the uterus 3. When expulsion with the aid of prostaglandin fails the colpotomy approach for removal of a mummy is feasible. It is performed under epidural anesthesia.

Exposure varies with the flexibility of the broad ligaments hence is better in older cows.