Equine - Pregnancy Loss and Pathologic Pregnancies Flashcards
When is pregnancy loss the most common?
in early pregnancy - within the first 35 days
15-20% of mares will lose pregnancy before day ____.
50
Up to 30% of mares will lose a pregnancy by _______.
foaling
What pregnancy losses are most commonly noted and detected by owners?
mid to late term losses
Pregnancy loss occurs frequently prior to the diagnosis of ______ particularly in _______ mares.
pregnancy; subfertile
What can cause pregnancy loss?
stress, endocrine imbalance, poor uterine environment
What stressors can cause pregnancy loss?
transport (not recommened until after 40 days of gestation), introduction to new groups, severe heat, significant work
What endocrine imbalances can cause pregnancy loss?
Cushing’s or Metabolic Syndrome
What disease processes can cause poor uterine environment that leads to pregnancy loss?
endometrial cysts, glandular fibrosis, and endometritis
True or False: Endometrial cysts can only cause late term pregnancy loss.
false- it can cause pregnancy loss at two different stages
How can endometrial cysts cause early pregnancy loss?
large intraluminal cysts can interfere with maternal recognition of pregnancy - interfere with embryonic movement
How can endometrial cysts cause mid to late-term pregnancy loss?
Large or multiple cysts may lead to placenta insufficiency
What can cause an increase in size and/or number of endometrial cysts?
lymphatic obstruciton, endometrial fibrosis, and endometrial glandular changes
How are endometrial cysts diagosed?
via transrectal ultrasonography
It is paramount to document what about endometrial cysts?
their size and location at the time of ovulation prior to pregnancy diagnosis
Where may endometrial cysts be located?
they may be luminal or intramural (lymphatic vs. glandular)
How can endometrial cysts be shaped?
ovoid, multilobular, or perfectly spherical
How are endometrial cysts treated?
hysteroscopic endometrial laser ablation
When can periglandular fibrosis cause pregnancy loss?
early, mid, or late-term losses
What age of mares typically get periglandular fibrosis?
older mares
What is periglandular fibrosis?
Increased layers of fibrocytes surrounding endometrial glands with glandular nesting
How is periglandular fibrosis diagnosed?
via endometrial biopsy
What % chance of foaling will a mare have if she is diagnosed with stage IIb periglandular fibrosis?
10-50% chance of foaling
What % chance of foaling will a mare have if she is diagnosed with stage III periglandular fibrosis?
<10% chance of foaling
What is the treatment for periglandular fibrosis?
none - the affected mares may be candidates for assisted reproductive techniques
What are some genetic and embryonic causes of pregnancy loss?
Embryonic factors, chromosomal abnormalities, genetic developmental abnormalities, and intrinsic factors with particular stallions and mares
What are some infectious causes of pregnancy loss and high-risk pregnancies?
endometritis (bacterial and fungal), placentitis (ascending, nocardioform, or hematogenous), leptospirosis, Equine Herpes Virus (EHV-1 and EHV-4), Equine Viral Arteritis Virus, and Potomac horse fever
What percentage of pregnancy loss is caused by placentitis and when does it occur?
20-30%, loss occurs late in gestation (8-10 months)
What are the types of placentitis?
ascending placentitis, hematogenous placentitis, and nocardioform placentitis
What is the most common type of placentitis and what is it caused by (general)?
ascending placentitis - multiple bacterial species are implicated
What is hematogenous placentitis an extension of?
bacteremia or viremia to seed the placenta leading to diffuse placentitis - may see clinical signs attributable to systemic infection in addition to abortion
What causes Nocardioform placentitis?
Amycolatopsis species, Crosiella equi, or Streptomyces species
What bacteria are commonly associated with ascending placentitis?
Streptococcus equi subsp. Zooepidemicus, E. coli, Klebsiella pneumoniae
What is the pathophysiology of ascending placentitis and fetal death.
There is bacterial colonization of the chorioallantois, then colonization and replication within the allantoic cavity, umbilicus, and amniotic fluid. This leads to increased inflammatory cytokines and prostaglandins. Uterine contractility is increased. There is an altered hormonal provile and activation of the HPA axis leading to abortion or delivery of premature, severely compromised foal.
True or False: Abortion due to placentitis often occurs without any premonitory signs.
TRUE
If a mare has clinical signs due to placentitis, what would they be?
early mammary development and/or secretions
How is placentitis diagnosed?
via transrectal ultrasound assessment of the combined thickness of the uterus and placenta (CTUP)
What should the CTUP be at days 271-300 of gestation?
<7 mm
What should the CTUP be at days 301-330 of gestation?
<10 mm