27: non infectious pregnancy loss Flashcards

(92 cards)

1
Q

what is early embryonic mortality?

A

loss of conceptus prior to maternal recognition of pregnancy (MRP)

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2
Q

what assumption regarding the mare’s fertility usually follows early embryonic mortality?

exception?

A

assumption is sub fertility / infertility

except: mares

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3
Q

t/f

after early embryonic mortality, a FM will have regular return to estrus

A

true

NO MRP occurred so cycles continue as normal

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4
Q

what does the term early embryonic death imply?

A

embryonic losses that occur prior to time of abortion

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5
Q

late embryonic mortality is defined as what?

A

embryonic loss btwn MRP and completion of organogenesis

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6
Q

how does late embryonic mortality affect FM return to cycling?

A

pseudo pregnancy occurs b/c MRP has occurred

irregular return to estrus occurs as a result

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7
Q

what is a resorption?

what is dispelled from the FM?

A

embryonic (or early fetal) tissues break down and components are dispersed

“flimsy” parts of embryo can be absorbed thru endometrium after embryonic loss

FM may have discharge (this is often inapparent) but no discernible conceptus is expelled

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8
Q

what is mummification?

A

death of 1 or more fetuses in the absence of ascending bacT infection

fetuses and placentas become dessicated via absorption of fetal fluids

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9
Q

when mummification occurs, what is usually occurring in FM repro tract during this time?

A

CL present (pseudopregnancy occurs)

cervix NOT dilated

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10
Q

mummification MC occurs in which species?

A

cattle
swine
Pygmy goats

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11
Q

t/f

PgF2a can be given to cows to resolve cases of mummification

A

false - some require surgical removal, especially if cow is valuable

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12
Q

what is maceration?

A

occurs w death of fetus in the presence of bacT infection

macerated fetus may, rarely, be retained w/in uterus

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13
Q

what occurs in FM repro tract when maceration occurs?

A

luteolysis eventually -> cervical dilation -> additional colonization of fetal tissues by ascending organisms

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14
Q

what species MC experiences maceration?

A

cattle

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15
Q

what is an abortion?

A

expulsion or delivery of a fetus, live or dead, that is incapable of life outside of the uterus due to pre maturity

it is NONVIABLE

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16
Q

when does an embryo become a fetus?

A

once differentiation / organogenesis is complete?

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17
Q

what is late term abortion?

A

abortion occurring in late gestation or near to term

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18
Q

what is still birth?

A

offspring born dead or found deceased shortly after birth at term

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19
Q

what is MC reason for still births?

A

severe hypoxia during parturition

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20
Q

what makes a fetus viable or non viable?

A

its ability to live outside the FM

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21
Q

at what point can you determine that a fetus is viable?

A

you cannot - you can say that it is alive but you cannot say it is viable until it shows that it is viable once it is born

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22
Q

what are some non infectious mechanisms of pregnancy loss?

A
  • genetic abnormalities of embryo / fetus
  • physiologic stress, including systemic (non repro) illness
  • toxins
  • placental insufficiency
  • endocrine abnormalities
  • iatrogenic through administration of abortifacient pharmaceutical cocktail -> intentional or inadvertent
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23
Q

why is the embryonic period relatively tenuous in the mare, especially during her first 35 days of pregnancy?

A

preg maintenance dep on CL

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24
Q

what is the embryonic mortality rate in the mare?

due to what problems most commonly?

A

2.5-25%

intrinsic reproductive, extrinsic, embryonic

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25
what are the intrinsic causes to embryonic mortality loss in the mare?
foal heat breeding endometrial degeneration progesterone deficiency
26
how common is progesterone deficiency in the mare, leading to embryonic mortality in the mare?
rare
27
what is intrinsic embryonic mortality loss in the mare due to (d/t) foal heat breeding issues caused by? when can it occur relative to MRP?
some loss is to be expected d/t incomplete involution, residual inflammation when embryo arrives in uterus 5 d post fertilization loss may occur before or after MRP
28
what is the condition of endometrial degeneration in the mare?
poor histotroph production - endometrial gland duct constricted by fibrosis - interferes w effective implantation
29
t/f endometrial degeneration is age related
somewhat true - somewhat age related by not entirely
30
does endometrial degeneration in the mare affect pregnancy before or after MRP? what type of pseudopregnancy occurs?
after MRP pseudopregnancy type 1
31
why is some loss during foal heat expected?
less fertile b/c of hospitality of uterine environment - less likely for the embryo to survive the uterus during this time
32
what are some extrinsic causes of pregnancy loss in the mare?
physiologic "stress" | nutrition
33
how does physiologic stress cause embryonic mortality in the mare?
lysis of the primary CL
34
what might cause physiologic stress in a mare?
inc ambient temperature heavy work transport endotoxemia
35
t/f nutrition has a significant effect on embryonic mortality in the mare
false this is unlikely embryo is small and nutritional needs are very small AND is equipped with its own supply in the yolk sac
36
what are embryonic or 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 incompatibility - RARE mare-jack breeding - failure to produce endometrial cups
37
when might placental insufficiency occur in the mare? what is the result
- body pregnancy - twinning abortion
38
what is body pregnancy in a mare? what does it cause and when?
embryo implants in abnormal loc in the uterine body placenta expands into both horns but is relatively insufficient abortion at 8-9 months fetus may be alive at delivery but NOT viable
39
what is the MC diagnosed cause of equine abortion? what % of cases? *****
twinning 20-30% of cases
40
what is the mechanism of twinning that leads to placental insufficiency in mares?
one fetus occupies a uterine horn and the boody and the other only the uterine horn as the fetus occupying the horn only grows, its demands for o2, waste disposal and nutrients begins to exceed the capacity of its placenta to provide them
41
how does twinning lead to abortion in mares? what is the condition of the foals born?
distress of the smaller fetus signals birth so both fetuses are delivered often one is alive but is not viable and small one is dead
42
why is a mummy foal sometimes born with twins?
if the distress signal from the smaller fetus is not strong enough, the smaller fetus dies and mummifies and is delivered at term w a live foal
43
when is abortion of twins signaled in mares?
mid to late gestation
44
what signal from the stressed fetus of twins in the mare cause endocrinologically? when does this event normally occur?
dec e2 inc 5a pregnanes normally occurs at end of gestation - shifted to mid/late gestation
45
what are the possible outcomes of twinning in mares?
- birth of one live foal and one mummy foal at term - delivery of 2 live foals in later term abortion -> poor viability - incredibly rarely, birth of 2 live, viable foals at term - inc risk for dystocia the later in gestation the abortion occurs and w foals delivered at term
46
which outcome of twins in the mare is the MC result?
delivery of 2 live foals, neither of which is viable
47
what complications of the mare's health are associated w twinning?
- retained fetal membranes -> metritis -> endoeoxemia -> laminitis - delayed uterine involution, therefore do NOT breed back on foal heat
48
what are 2 likely causes of embryonic mortality in cattle?
nutrition deficiencies | heat stress
49
what nutrition deficiencies are associated with embryonic mortality in cattle?
def in Cu, Se, Mn
50
how does heat stress lead to embryonic mortality in cattle?
cow unable to cool off - malformations in embryo, embryonic death CL may be susceptible to lysis
51
what toxins lead to embryonic mortality in cattle?
- endophyte-infected tall fescue | - nitrates
52
what is the pathogen in endophyte infected tall fescue?
Acremonium coenophialum
53
what does endophyte infected tall fescue cause in cattle, that leads to embryonic mortality? before or after MRP?
- significantly lower preg rates if grazing heavily infected grasses - before or after MRP
54
how does ergovaline affect pregnancy? what season is it MC?
- ergot-induced hyperthermia => luteolysis | - MC in mid to late summer
55
what are some sources of nitrate intoxication?
- nitrate accumulating plants [sudan grass, johnson grass, pigweed] - drought-damaged corn [green stalks and stubble] - heavily fertilized pastures
56
what is the patho-physiology of nitrate intoxication?
- nitrate converted to nitrate in rumen => nitrate enters circulation, oxidizes ferrous (Hb) to ferric iron (MHb) => MHb does NOT bind o2 -> hypoxemia => fetal hypoxia -> stress, death -> triggers abortion
57
what stage abortions tend to occur in cattle with nitrate intoxication?
late gestation abortions
58
t/f nitrate intoxication that causes abortion often causes acute death of the dam
false low levels of intoxication cause abortion that do NOT kill the dam
59
what toxins cause systemic maternal compromise?
- cyanogenic sugars from johnson and sudan grass - pesticides applied to alternative forages being fed due to poor crop performance and drought [soybeans] - aflatoxins in drought-damaged corn
60
how does pine needle consumption lead to abortion?
vasoconstriction of caruncular vascular bed - > dec blood flow to placenta - > fetal stress - > peripheral endocrine cascade - > fetus premature delivery / abortion
61
how much pine needles does a cow need to consume to experience side effects?
a lot..... over 2 kg/day | for 3 days
62
what compound is the toxin in pine needles?
isocupressic acid
63
what stage pregnancy loss occurs with pine needle intoxication?
late-term abortions
64
what is a common management strategy for cattle and pine needle abortion?
- abortions will begin about 2 days after ingestion begins - remove cows - abortions stop 2 days later - balance cost of grazing/not grazing against the possibility of abortion - calculated risk
65
what does locoweed cause in cattle [Astragalus and Oxytropis]?
abortion at any stage of gestation, fetal malformations depends on the stage of gestation during consumption
66
is locoweed intoxication acute or chronic?
chronic - due to 4-6 wks of ingestion
67
what compound in locoweed is toxic?
indolizidine alkaloid swainsonine
68
what is the patho-physiology of locoweed intoxication?
- inc fetal vascular resistance - > cardiac insufficiency -> fluid accummulation -> fetal death -> abortion
69
what iagrogenic causes of abortion occur in cattle?
- anadvertent administration of PgF2a btwn 1 wk and 3-5 mos of pregnancy - AI of cows believed to be in heat but that were actually pregnant [depends upon how far into cervical canal insemination was performed]
70
PG should induce abortion until 5 mos, so why is 3 months the rule?
b/c some failure occurs d/t individual variation and it will cause abortion at 3 mos so do NOT give PG btwn 1 wk and 3 mos of pregnancy
71
what is the embryonic loss in does? why?
20-30% stress or trauma b/c preg maintenance is solely CL dependent
72
what causes embryonic loss in small Ru?
- heat stress, trauma - rough handling, shearing of ewes, predator attacks - extreme maternal malnutrition - genetic abnormalities of the embryo - medication administration - toxins
73
what medications can cause embryonic loss in small Ru?
- inadvertant PgF2a | - high doses of albendazole
74
toxins that cause embryonic loss in small Ru?
- phytoestrogesn in plants inc embryonic mortality | - veratrum californucum - teratogenic effects 6
75
what is the background rate of abortion in small Ru?
less than 5%
76
what toxins cause embryonic loss in small Ru?
nitrate poisoning | locoweed
77
what does pregnancy toxemia cause in small Ru? MC in goat or sheep?
abort in latter / terminal stage of pregnancy: goat more sensitive to this b/c all she requires is luteolysis less common in sheep b/c also have p4 from placenta so harder to abort sheep than goats
78
what are non infectious causes of preg loss in sow?
- stress / trauma - CO poisoning - inadvertent administration of PgF2a at ANY stage of gestation b/c CL dependent all the way thru pregnancy
79
non infectious causes of preg loss in the hembra?
- stress / trauma | - medication administration
80
what medications causes preg loss in hembra?
- exogenous corticosteroids even small amounts in ophthalmic ointment in 2nd half of gestation - single dose of PgF2a at ANY stage of gestation [b.c CL dep all way thru gestation]
81
what is the expected rate of pregnancy loss in the bitch by 8 wks of gestation?
11-13%
82
what are non infectious causes of preg loss in bitch d/t?
- genetic abnormalities [in line breeding] - hypoluteodism [luteal insufficiency] - medication administration
83
how common is hypoluteodism in the bitch?
not common - only a few documented cases
84
what occurs during hypoluteodism?
- p4 begins to decline abnormally btwn d25-35 | - is lower than average by day 35-40
85
what might supplementation with altrenogest cause in pregnant bitches?
- masculinization of FM fetuses - cryptorchidism in M puppies - requires twice weekly p4 measurement and fetal monitoring
86
what does exogenous corticosteroids cause in pregnant bitches?
abortion
87
what does chloramphenicol cause in pregnant bitches?
fetal death
88
what is the typical profile of p4 in pregnant bitch?
p4 rises and peaks at 25 days
89
t/f it is commonplace to give a pregnant bitch drugs to help her through her pregnancy
false it is best to give her no drugs during her pregnancy unless absolutely necessary
90
what are genetic defects d/t in the offspring of a queen?
inbreeding
91
what causes embryonic mortality, abortion, congenital malformations in the pregnant queen?
nutritional deficits vit A taurine
92
t/f avoid giving drugs in the queen during pregnency
true