Dystocia Cases

Question 1

• Bumble a 7-year old Golden Retriever bitch was mated on 26th and 27th February (timed on the basis of increased progesterone) and went out of oestrus shortly after that
• She was confirmed pregnant at ultrasound examination on 26th March when two conceptuses were identified
• Rectal temperature was consistent at approximately 38C when measured twice daily until 3 days ago (2nd May) when it declined temporarily to 37.4C
• She developed a red-green vulval discharge last night (4th May). Ultrasound examination this morning shows this appearance

What is going on in this case?

Answer 1

• There is no heart beat on US of the puppies
• Can see ribs, can see junction between abdomen and can see heart - it is stationary and no anechoic cavities - its heart is clearly almost solid in its appearance
• So at least 1 dead puppy so far…
• In terms of history:
• It was likely they got the timing of breeding roughly correct, so probably mated 2-4days post ovulation - good planning
• Would expecting parturition 58-72 from mating, but we know when this dog ovulation - so 63 days from ovulation.
• Rectal temperature, went down, this is a sign they are about to whelp and this happens because of the decline in progesterone, as it is generally considered to be thermogenic and maintain body temp, so if sudden fall - lost thermogenic effect. Progesterone falls and then commonly a reduction in body temp, usually recovers
• Progesterone dropped to basal values due to CL regression, this is due to fetal cortisol. Stressed fetus, results in cascade event - results in reduction of progesterone essentially
• Fall of progesterone - softens cervix, allows uterine contraction (usually suppresses them, but then it goes away so stops suppressing them), looks like should have happened on the 2nd May… now on the 4th May
• Red green vulval discharge now on the 4th May - comes from the zonary placenta, unusual placenta where the edges of the placenta, there is this intimate attachment between placental tissue and uterus, and when this is pulled away - release of old blood with pigment in it - can be green/brown coloured
• So pregnancy length about right, fit in with dates of ovulation and mating, rectal temp falls as progesterone falls and parturition presumably started as at least one of the placentas started to separate - and now she is scanned and she has at least 1 dead pup
• THIS IS THE COMMONEST TYPE OF DYSTOCIA - PRIMARY UTERINE INERTIA. Parturition starts but then doesn’t progress
• Secondary is when contraction cease following obstruction, uterine gets tired. Primary - don’t even get to this stage

Question 2

Do you need any further information or diagnostic tests in Bumbles case?

What are you going to do next?

Answer 2

• Image the other conceptus to see if it’s still alive -
• If it is alive could: go to caesarean - something that would be really sensible, or could also give oxytocin - try to initiate uterine contractions.
• To decide: quite likely each foetus is large as there are only 2! May be part of reason of inertia in the first place? If going to give oxytocin, the other might get stuck! Might end up with long period of parturition! If other fetus is there and not well and alive, then it’ll be made worse by giving oxytocin really as will reduce blood supply! Parturition occurring quickly chances is low! So takes longer to get alive one out. Down side to C-section is the sedation and anaesthetic
• So next thing to do is scan the fetus and make a decision

Question 3

On Bumbles clinical exam:

• Heart Rate 130
• Resp Rate 24
• Rectal temperature 38.9C
• Progesterone 0.4 ng/ml
• Calcium 7.5 mg/dl
• Endoscopic exam of vagina as shown

1. What can you identify?
2. As Bumble is 7 years old she will not be bred again. Will you remove the uterus and ovaries at the same time as performing the caesarean?

Answer 3

1. Can see discharge material running out, bit of fluid pooling. Cervix is relaxed. Calcium is just under the normal limit
2. A number would consider removing the uterus and lots of arguments for not - principally around risk to bitch. If the pups were alive would you do the same? If pups alive - yes, gary would as would still be worrying as a case of primary inertia, that giving oxytocin will take a long time… basis of small litter size would make him want to go to C-section

Question 4

What is the mechanism for the development of primary uterine inertia?

How do these cases present?

What information was present in the clinical history that could have suggested a problem was likely?

Answer 4

• Always advise clients about recording rectal temp twice a day
• Risk factors for inertia - likely associated with poor fetal signal or limited ability of dam to respond to the signal
• If small litter - not enough fetal signal
• Large litter - uterus stretched, limited ability to effectively contract and push puppies into birth canal
• Train owner to look for uterine contractions
• If you talk to an owner and talk about contractions, they misunderstand and think about forceful abdominal contraction, but difference to do with uterine contractions. Might be a failure of progression onwards, so often no abdominal contractions at all - want to look for UTERINE contraction e.g. seeks occlusion, goes off food - can sometimes see from side, but isn’t forceful abdominal pish that people think about

Question 5

What is the cascade of events for primary uterine inertia?

Answer 5

• Progesterone falls (stage of preparation)
• Uterine contractions commence (first stage parturition occurs but may be weak)
• Uterine contractions cease
• Abdominal contractions do not occur (no second stage parturition)

Question 6

When is primary uterine inertia usually seen?

Answer 6

–Small litter

–Large litter

–Old dam

–Obese dam

–Debilitated dam

Question 7

What happens when you get primary uterine inertia?

Answer 7

• Parturition does not progress
• Ultimately placentas separate (green discharge from marginal region of placenta)
• Fetuses die

Question 8

What normal feature of pregnancy in dogs complicates the diagnosis of primary inertia?

Answer 8

See a failure of true onset of parturition and signs can be missed by an owner. Can have essentially clinical signs being missed all together and confusion is around pregnancy length of the dog - can start from 58-72 days - VARIABILITY IN PREGNANCY LENGTH

Question 9

What is the physiology of fertilisation?

Answer 9

• Eggs hang around in repro tract waiting to be fertilised, 2-6days post ovulation is usually the time, a dog can still get pregnant is mated early as long as sperm still alive when the eggs become fertilisable
• Hormonal lengths of pregnancy is consistent - just depends when the dog get mated in relation to ovulation
• Pregnancy is 63 days from ovulation

Question 10

How can pregnancy length look long or short depending on time of mating?

Answer 10

Question 11

What management practices can be put in place to monitor these cases with primary uterine inertia?

Answer 11

Progesterone drops to basal values, which occurs a period of time before parturition

Question 12

How does rectal temperature change with regards to pregnancy and parturition?

Answer 12

Rectal temperature decreased by 1C between 10 – 14 hours after progesterone decreased to less than 2 ng/ml (≈ 6 nmol/L)

First rectal temperature less than 37 C was associated with parturition within maximum of 38 hours

Question 13

Describe the appearance of these cervix

Answer 13

Cervix changes

• Top left - week before parturition, thick mucus plug
• Top right - 2d before birth, lots of bubbles present within it
• Bottom left - immediately before
• Bottom right - before placental separation

Question 14

How does the appearance of the cervix change at day:

1. -10
2. -7
3. -1

In relation to parturition (0 being birthing)

Answer 14

•Day -10

–Os closed

–Tacky clear mucus

•Day -7

–Larger volumes of clear mucus

–Vaginal wall oedema

–Increased vascularisation of vagina

•Day -1

–Slight opening and increased mucoid discharge noted at

-6 hours

Question 15

At the time of presentation of a presumed overdue bitch, what information might be helpful?

Answer 15

At the time of presentation of a presumed overdue bitch / case of primary uterine inertia / obvious case of dystocia the following information may be helpful

• Mating dates and other information relating to oestrus
• General clinical examination
• Digital / endoscopic examination
• Ultrasound examination
• Radiographic examination
• Measurement of plasma progesterone

Question 16

When it is clear that inertia has occurred but before the pups have died what treatment options are available?

Answer 16

• Could have looked at bitch during pregnancy - get estimation of size of fetus and therefore its age. Can measure head diameter
• Detection of cases earlier
• If we were earlier in bumble and should know parturition is imminent - now know that we have uterine inertia, could we give oxytocin at this time? Yes we could, but challenge in this case is the litter size as small litter, likely big pups! If big litter, challenge of oxytocin is that a normal birth might take 8-12h, oxytocin has shorter half-life - might give some, shell have a pup or two, then another dose, another 2 pups etc. - dog tired, pups debilitating, owners tired, owner fed up etc. - for a small litter and big litter, oxytocin might not always be the best way forward!

Question 17

When is using oxytocin contraindicated for dystocia or parturition?

Answer 17

•Oxytocin

–Oxytocin doses are often too high and cause tetany not coordinated contractions

•0.04 IU/kg is appropriate given every 30 mins for 3 doses (30 kg Labrador = 1.2 IU = 0.12 ml of 10 IU/ml)

–Oxytocin compresses placenta and worsens fetal hypoxia so is contraindicated if fetuses are bradycardia

Question 18

What effect does calcium have on uterine contractions?

Answer 18

–Concurrent calcium administration improves uterine contractions

Question 19

If you delivered pups via c-section, but the bitch had no milk what treatment options would you consider?

Answer 19

• ‘Agalactia’
• How do they present differently? No milk at the nipple - might be that there is no milk but not being let down, treatment for this is to give oxytocin (e.g. through c section, everything is normal and milk let down will turn on in 12h) or there might not be any milk production, oxytocin will not fix this!
• If no milk production, cannot buy prolactin, can buy a drug that will be an agonist - commonly available is metaclopramide, act as a dopamine antagonist and can help with milk production

Question 20

What do prolactin agonists do?

Answer 20

Stimulation of milk production

•Prolactin agonists are dopamine antagonists

–Metoclopramide at 0.1-0.2 mg/kg, SC, tid-qid

–Phenothiazines at low dose may also stimulate mild production

Question 21

Tell me about the ultrasound images of these three fetuses

(should be a video so diffiuclt to tell)

Answer 21

• Top - alive, less than 60bpm, its usually 2-3x maternal heart rate! Count fetal heart rate, why are they bradycardic? Because they are hypoxic! They don’t have enough oxygen so they drop their HR to compensate, stressed fetuses - significantly compromised due to hypoxia. Relate degree of bradycardia to outcome - the more hypoxic they are, the more bradycardic they will be, the faster input required. Fetal HR does go up when its stressed as an immediate response (will see on TV in humans), but usually we don’t see this in animals, will go to bradycardia after the initial tachycardia!
• Middle - bradycardia
• Bottom - dead puppy, no heart beat

Question 22

Some comes in with a french bulldog and asks for an elective C-section and wants to be given a set day for it.

What do you do, what do you need to consider?

Answer 22

• Brachycephalic breeds, designer breeds etc. - common!!!
• Ethics associated - will you do an elective C-section? Difficult to say no if dystocia! But difficult to say yes and encourage proliferation of some of these breeds. What is practice policy?
• Say - let’s have a chat, explain what happens normally and sequences of what happens and on the basis that the fall of rectal temp occurs 24-36h before initial stage of parturition, we ought to be able to plan that and get you to observe that and there is still enough time for a rapid c-section rather than a planned one - so its at the right, natural time. Don’t really know when it ovulated, could be doing a c-section or planning to do one too late, or doing it too early. When its too late or too early, will be our fault rather than their fault for not doing the right things in terms of understanding physiology!
• If he says no to doing this and wants to set a date for C-section - what will we do?
• Don’t want to go too early, could end up with fetus that’s not suitable mature e.g. no lung surfactant, they might fade and die. Don’t want to leave too late and cause a dystocia, but probably going later and leaving the owners with the advice of the rectal temp etc. is probably better
• Go In the middle and say 65 days - could be 1 week early? Could be borderline. Going before 65 days with no other information is tricky!! Got to 64/65 days just in case it’s a 72 day pregnancy

Question 23

How can you use information collected at the time of mating to predict parturition?

Answer 23

•Onset of parturition is consistently 63 + 1 day from ovulation

– A variety of markers of ovulation are clinically useful

• Progesterone ≈ 2.5 ng/ml (8 nmol/l) at the LH Surge
• Progesterone ≈ 7 ng/ml (21 nmol/l) at ovulation
• Progesterone ≈ 10 ng/ml (32 nmol/l) 2 days after ovulation
• Progesterone ≈ 25 ng/ml (80 nmol/l ) at the end of the fertilisation period

Question 24

How can we use embryo/fetal measurements to predict parturtion?

Answer 24

•Examples:

–Gestational sac diameter

–Head diameter

Gestational age = (6 x gestational sac diameter [cm]) + 20 Gestational age = (15 x head diameter [cm]) + 20

Thus, Days to parturition = 63 – Gestational age

N.B. these measure are size/breed-specific

Small breeds (<9kg) + 1 day to the calculated GA Giant breeds (>40kg) – 2 days from the calculated GA

Question 25

How can we use embryo/fetal assessments to predict parturtion?

Answer 25

•Examples:

–Detection of specific characteristics of the pregnancy

–First appearance of the embryo proper

–Regression of the yolk sac

N.B. These parameters are consistent across breeds

– Detection of organ development

Question 26

With normal parturition and the stage of preparation, what happens in the lead up to it? e.g. progesterone, rectal temperature, tissues and discharge etc?

Answer 26

• Progesterone declines
• Rectal temperature declines
• Vulval and perineal tissues relax
• Nest making
• Mucus vulval discharge

Question 27

With a normal parturition, what is the first stage?

How long does it take and what do we see?

Answer 27

•Onset of uterine (not abdominal) contractions

–Bitch restless, pants, anorexic

•Pup pushed against cervix

–Cervix dilates

–Outer membrane may break

– fluid may be seen at vulva

• 1- 12 hours in duration
• Milk present in mammary gland

Question 28

Read the radiograph and tell me what you would do

Answer 28

• How many pups? Count the skulls and spines?? Small number - looks about 3? Likely to be big based on this small litter size
• First one if stuck!! Likely because its big
• Difficult to know whether they are alive or dead from radiograph, changes that we get on radiograph take several days to occur
• Might go to c-section from this
• Benefits to radiograph? In terms of understanding how many there are, put transducer on and could obstruct the others - more difficult to guess fetal number with US compared to X-ray

Question 29

Read the ultrasound and tell me what you would do

(difficult as not a video)

Answer 29

• Can see hart beat, bladder and stomach
• Anything else unusual - skin in transverse plane of view, lots of oedema present - fetal anasarca - huge puppy

Question 30

Read the radiograph and tell me what you would do

Answer 30

• 2 pups
• There is gas, but it’s in rectum - rectum displaced dorsally due to uterus
• Start of overlapping of skull bones on more ventral one - sutures don’t align
• In more dorsal one - spine curves right around on itself, may be a fetus that’s developmentally abnormal or in later signs of fetal death, get distortion of fetal skeleto

Question 31

Read the radiograph and tell me what you would do

Answer 31

• Accumulation of gas - fetal death
• In late fetal death - putrefaction, 3 days or more fetal death - free gas in lumen of uterus
• Distortion of outline of fetus