Pregnancy Loss Causes and Consequences Flashcards
- Gala Girl starts foaling at 332 days after breeding
- She was restless and flank watching for 3 hours before starting active abdominal contractions which have now been present for 30 minutes
- Are these events normal?
- What can you see now?
- What does this indicate?
- Do you need to take any actions, if so what?
- If the foal is delivered alive might there be any consequences?
- Failure of progression
- Need to know normal mare parturition timeline
- Some signs
- Mare – short uterine before abdominal (1 hours, and 3 hours is deffo upper limit)
- After 30 mins of straining would expect part of the foal to be devliered
- Red bag devery – breaking of the placenta; being pushed out before the foal but should come out through the star
- Yes we need to act as this as been going on for too long and the foal is likely to be hypoxic
What does fetal loss usually results in?
Abortion
Why does fetal mummification not happen very often?
Fetal mummification does not occur in the absence of twins since usually after death there is abortion. Most causes of death occur late in pregnancy and after the switch from luteal to placenta. Placenta supporting progesterone loss – expel fetus
What is the exception to fetal mummfication happening?
cervical abnormality which prevents expulsion
What causes persistence of endometritits?
•Presence of bacteria or inflammatory products within the uterus as a result of mating-induced endometritis creates a hostile uterine environment and prevents the mare from staying pregnant (when the conceptus enters the uterus on day 5/6)
What is the pregnancy rate after the following durations of endometritis after ovulation?
1 day?
2 day?
3 days
4 day?
5 days?
75%
65%
32%
11%
0%
What is the effect of venereal pathogens on embryonic death?
•Mares with any of the venereal pathogens may get pregnant but may fail to stay pregnant because of a hostile uterine environment as discussed earlier
•
•Venereal more likely to cause endometritis which then causes pregnancy loss! In terms of later pregnancy loss these pathogens aren’t so relelvant
When does early inter embryo inhibition occur? (3)
What is the mechanism?
–This appears to be a natural method of reduction of one of twins
–It only occurs post fixation
–It only occurs when fixation occurs within the same horn
–The mechanism appears to be some specific inter-embryo inhibition
–The twins that go on to abort later usually originate from conceptuses that have fixed in opposite horns so that this mechanism has not occurred
How liekly is it for a luteal insufficiency to cause embryonic death?
Theory - low progesterone
little evidence of this in the mare! Supplementing progesterone is probably of little benefit. Risk period can be before endometrial cups at the end of the CL! But is it needed the rest of the time when there are multiple CLS?
–Much anecdote on low progesterone concentrations causing pregnancy loss in mares
–Many mares especially in USA are given large doses of altrenogest (Regumate) over many days to ‘prevent’ this
–Some of these mares may have previously had pregnancy loss but in most the cause has never been documented as low progesterone
–One might consider when any risk period would likely be (perhaps day 20 to 40? – why?)
–In GE’s view the practice is bogus in the majority of cases
What can the secondary problem of a luteal insufficiency (low progesterone) be?
–Specific inflammatory or stressful situations may result in PG release
–This can threaten progesterone concentrations
–In some cases Altrenogest may be considered to help ‘protect’ the pregnancy (e.g. the early pregnant mare undergoing anaesthesia, mare with placentitis)
What is the Pregnancy loss rates for mares that have reached the stage of endometrial cup formation?
10%
Even tho non infectious is most comon, what needs to be considered as a primary concern?
Infectious
What is our next diagnostic step if there is a fetal abortion?
•Appropriate samples (fresh whole fetus, membranes and mare’s serum) should be sent to appropriate pathologist
Wat do we d if there is a suspicion of an infectious cause of abortion?
abortion plans must be implemented to isolate the infected mare and to prevent movement onto and off the stud
What are the non infectious causes of fetal abortion? (2)
- Multiple conceptuses
- Umbilical cord abnormalities
What is the incidence of multiple ovulations?
20%
What is the prevalence of twins at 14 days?
10% •(less in some breeds) – some may naturally resorb
What can an incorrect diagnosis at 14 days be caused by? (3)
–Incomplete examination of the uterus (conceptuses are mobile)
–Failure to recognise twins
–Confusion of endometrial cysts
What is the outcome of multiple conceptuses?
- Outcome is rarely successful as a result of competition for placental attachment area (see case in Week 1)
- Competeing for the placenta and the attachment sites
When do we plan examinations for multiple conceptsues?
–Day 14 and if suspicion of twins then re-examine 2 days later
–Day 21
–Day 35
What can be seen?
Crushing twin by pressure of transducer and subsequent appearance of crushed conceptus
What is this?
Fetal death associated with umbilical cord torsion
Torsion of UC = fetal death
•In some cases it is longer than normal and may be twisted (obstruction) or may constrict around a fetal extremity resulting in fetal death
What is this?
Abortion of fresh fetus within fetal membranes associated with EHV1 infection
- One of a group of 30 unvaccinated national park ponies aborts in late pregnancy.
- Examination of the fetus confirms that this is Equine herpesvirus 1
- The ponies cannot be isolated except in adjacent outdoor paddocks.
- Somebody should do something about it. What can be done?
- Thckened oedema placenta – typical of herpes. Check for ascending placentitis (problem likely to be focussed around cervix)
- Here we have a late term pregnancy and an animal which is potential infectious and can spread to other incontacts. Need a regime to manage infection so need to manage mare to mare transmission.
- This foal could be infected – in a herd of abortion. There is a risk the foal has herpes which it will transmit. The foal may surcum to neonate disease
- Many of the herd animal are likely to have been infected some time previously.
- Only thing available to vaccinate in face of an abortion outbreak - once identified you would isolate and vaccinate
What is seen in a hrse with EAV?
Raised nodular lesions
Ventral and scrotal oedema
Occular swelling
What is this?
Intact cervical star where placenta should rupture and the foal leaves within amnion
- Sophie is 12 year old primigravida at 290 days of pregnancy. She has poor vulval conformation managed when 21 d pregnant with a Caslick procedure
- Currently she has a purulent vulval discharge. Trans-abdominal ultrasound shows the combined thickness of the uterus and placenta to be 18 mm
- What is likely going on?
- What treatment are appropriate?
- Are there any risks with the treatments you propose?
- At what gestational age would the foal likely survive?
- Thick placenta
- Caslick used to prevent ascending placentitis
- She has got a placentitis
- 40 days to go
- Foal will be struggling due to abnormal placenta. Foal may be septic.
- Would induce parturition butfoal unlikely to survive.
- Want to try to manage to keep foal in the mare to allow it to grow and survive
- Could then induce parturition closer to term
- Give antibiotics I/U through cervix but don’t want to penetrate the friable oedematous placenta!
- Pus will come out
- Antibiotic pessary or tablet and digitally poke through the cervix
- Some put on progesterone
- Systemic AB will have limited penetration
- Then induce when ready (use eye size to estimate age)
- 310-315 days should survive (ish). Better to work out gestational age by size.
What is the normal combined placenta uterine thickness at day:
150-270?
271-300
301- 330
331+
In pregnancy
