Lecture 27 - Non-infectious causes of Pregnancy Loss Flashcards
Define early embryonic mortality
Loss of conceptus prior to maternal reconition of pregnancy (MRP)
T/F: Early embryonic mortality is the same thing as early embryonic death.
False
Early embryonic mortality is inapparent, except in ______, so assumption is subferitlity/infertility.
Mares
Early embryonic mortality leads to a _____ return to estrus.
Regular
Define late embyronic mortality
Embryonic loss between MRP and competion of organogenesis and leads to pseudopregnancy or irregular reutrn to estrus, depending upon cause of pregnancy loss.
Define resorption
Embryonic (or fetal) tissues break down and components are dispered.
No discernible conceptus is expelled (some tissues may be discharged, but it iwll uslaly be inapparent to owner)
Define mummification
Death of one or more fetuses in the absence of ascending bacterial infection.
Usually in the presence of a CL and the absence of cervical dilation.
Fetuses and placentas become dessicated via absorption of fetal fluids.
Mummification is most commonly seen in:
Swine, pygmy goats, and cattle
In cattle, does administration of PGF resolve all cases of mummifcation?
No - surgical removal may be required
Define maceration
Occurs with death of fetus in the presence of bacterial infection.
Luteolysis eventually occurs resulting in cervical dilation and additional colonization of fetal tissues by ascending organisms.
Macerated fetus may, ararely, be retained within the uterus.
Maceration is most commonly seen in _____.
cattle
Define abortion
Expulsion or delivery of a fetus, live or dead, that is incapable of life outside of the uterus due to prematureity, i.e., it is NONVIABLE
An embryo “becomes” a fetus once differentiation/oragnogenesis is complete
Define late-term abortion
Abortion occuring in late gestation to near term.
Term is when the fetus is due; therefore, there cannot be suche a thing as “late term”
Define stillbirth
Offspring born dead or found deceased shortly after birth at term.
Most result form severe hypoxia during parturition.
Embryonic period relatively tenuous in the mare, particularly during hte first 25 days. Why?
Because she solely relies on her CL to maintain pregnancy
Intrinisc causes of embryonic mortality in the mare
Foal heat breeding
Endometrial degeneration
“progesterone deficiency” - RARE
Why does foal heat breeding lead to intrinisc cause of embryonic mortality in the mare?
Incomplete involution, residual inflammation when embryo arrives in uterus 5 days after fertilization.
Loss may occur before or after MRP
Endometrial degeneartion leads to embryonic mortality before or after MRP?
AFTER - leading to pseudopregnancy type I
Extrinsic causes of embryonic mortality in the mare:
Physiologica “stress” –> lysis of the primary CL
Nutrition - questionable b/c embryo is small, its nutritional needs are miniscule, and the embryo is equipped with its own nutritional supply (yolk sac)
Embryonic/fetal causes of embryonic and early fetal mortality in the mare:
- Chromosomal abnormalities
- Poor oocyte quality in mares of advanced age
- Spontaneous, sporadic chromosomal abnormality
- Immunogenetic influences
- Mare-stallion incompatability - RARE
- Mare-jack breeding - failure to produce endometrial cups
Mare-jack breeding leads to failure to produce _____
Endometrial cups
What is “body prengnancy” in the mare?
- Embryo fixes and implants at the body of the uterus (unusual - normally implants at base of horn so back legs grow into one horn, and front part goes into uterus)
- Placenta expands into both horns, but relatively insufficient space
- Abortion occurs at 8-9 months
- Foal often alive at delviery but not viable (bones haven’t ossified yet