Pregnancy and parturition in the bitch Flashcards
1
Q
How long is the gestation of a dog?
A
65 days +/- 24 hours from LH surge
63 days +/- 24 hours from ovulation
2
Q
How can we calculate gestation from the mating date?
A
57-73 days
LH surge = day 0
Mating can occur before that
Oestrus behaviours/mating excepted anywhere from day 0-5
Need to factor in how long the egg and sperm can survive
Always check which date an owner is basing their expected due date on
3
Q
Via what methods and when can pregnancy be diagnosed?
A
Ultrasound – day 25 onwards
Relaxin assay – day 30 onwards
Palpation- day 30 onwards
Radiography – day 45 onwards
4
Q
What is the most sensitive method of pregnancy diagnosis?
A
Ultrasound
5
Q
Describe the feature of ultrasound for PD
A
In smaller dogs having them held with their front legs in the air can help drop the uterus caudally and make imaging easier
Foetal heart beats can be detected from day 25 onwards – look for the ribcage. The lungs look heterogenous like liver (no air in them). Heart rates can also be counted
- Remember other processes can cause hypoechoic lesions e.g. pyometra, gastroenteritis
6
Q
What are the main benefits of ultrasound for PD?
A
- Rapid detection
- No sedation needed
- Assessment of foetal heart rates
- Foetal measurements possible
- Earliest reliable detection method
- Owners love getting a print out of the image!
7
Q
What are the limitations of ultrasound for PD?
A
- Accurate foetal count not possible
- Can see false negatives (scanned too early vs missed). If negative repeat in 2 weeks
- Operator learning curve
8
Q
Describe the relaxin assay for PD
A
Relaxin can be used from day 23, but is significantly more reliable from day 30
External lab test so delay in reporting results
Not commonly used
9
Q
Describe radiography for PD and why its used from 45 days onwards
A
- Foetal skeletal ossification occurs from day 42 onwards. Prior to this point you will not be able to differentiate between a pregnant uterus and fluid filled one.
- Day 45 gives this time to happen
- Less widely used in practice
- Bitch may require restraint and only operator safe way to do this is to use sedation
- Can count pups but not always easy
- Expensive compared to US
10
Q
How long does stage 1 of parturition take?
A
6-36 hours
11
Q
Describe the hormonal and behavioural changes that occur in stage 1 of parturition
A
- Drop in progesterone and rise in prolactin
- Temp drops below 37.5°C in large dogs and 37.0°C in small dogs when about to give birth
- Restless, anorexia, milk production, infrequent uterine contractions, nesting behaviour, vulval licking
- Cervix closed but gradually opens
12
Q
How long does stage 2 of parturition take?
A
2-12 hours
13
Q
Describe stage 2 of parturition
A
Rupture of the allenochorion of the 1st puppy
Strong regular straining -> puppy produced within 30 minutes
14
Q
Describe stage 3 of parturition
A
- Expulsion of placenta
- May be expelled with or after puppy
- Retained placenta unusual in dogs
- Lochia passed for approx 3 weeks
15
Q
How long is the interval between pups?
A
Interval between pups can be 5 mins to 4 hours
16
Q
When do we start to worry?
A
Signs of foetal distress
Maternal problems
Delays
17
Q
What are the signs of foetal stress?
A
Meconium visible (brown-yellow coloured) Green vaginal discharge without a puppy – indicator of placental detachment
18
Q
What are some maternal problems which would cause worry?
A
Vaginal haemorrhage
Exhaustion/collapse or other systemic disease signs
Severe pain
19
Q
After how long do we start to worry?
A
Foetus visible in birth canal with no progression to delivery
>30 mins strong contractions without a puppy
>4h between pups
20
Q
Define dystocia
A
Difficulty in giving birth
21
Q
What are some maternal factors linked to dystocia?
A
Uterine inertia: Primary or Secondary
Physical obstruction of birth canal e.g. narrow pelvis
22
Q
What are some foetal factors linked to dystocia?
A
Oversized foetus
Malpresentation
Malformation
23
Q
What is primary uterine inertia?
A
Failure to START stage two labour
24
Q
Primary uterine dystocia is associated with?
A
Can be associated with litter size;
50% cases <3 pups
Very large litter – myometrial stretch and inability to contract
25
What is secondary uterine inertia?
Failure to progress through second stage labour and complete. Usually after prolonged period of contractions
26
What are the causes of secondary uterine inertia?
Hormonal – lack of oxytocin
Fuel – lack of glucose/calcium
Maternal exhaustion
27
Investigation of dystocia should include what steps?
- Physical examination
- Ultrasound
- Radiography
- Blood tests
28
Describe the first step of investigating dystocia
Physical exam - should include a vaginal examination. This should be performed wearing sterile gloves and using sterile lubricant (not the tube used for thermometers
- Pups: stuck, malpresentation, in the birth canal?
- Ferguson's reflex
- Discharge
- Obstruction
29
Describe Ferguson's reflex?
Vaginal palpation should result in strong uterine contraction. Lack of this may indicate uterine inertia
30
How is discharge examined?
Is there any concerning discharge e.g. haemorrhage, green without a pup
31
Describe maternal ultrasound assessment when there is dystocia
Evidence of uterine rupture (free abdominal fluid/free floating puppies)
32
Describe foetal ultrasound assessment when there is dystocia
Viability – heart rate present?
| Distress – heart rate should ideally be >160, lower than this is an indicator of distress
33
How is radiography used if dystocia cases?
- Only way we can reliably count – important to know how many pups we are expecting
- Evidence of foetal death: gas around outside of foetus
- Measurement of foetal skull vs mothers pelvis
34
Describe the minimum database panel that should be collected from every blood test in an emergency patient?
```
The parameters measured are:
- PCV and total solids
- Blood glucose
- Lactate
- Creatinine
For dystocia cases Calcium should also be checked. Most in house machines measure TOTAL calcium, but IONISED is the active portion – ideal to check this!
If low then give a calcium bolus
```
35
Describe dystocia management
Dystocia cases may require medical or surgical management.
It is important in every case to ask the client if their priority is dam or pup – this may impact on your decision making and management choices. Never assume you know the answer to this!
36
Describe management of malpresentation
Gentle manipulation of pup using lubricant and sterile gloves
37
Describe management of secondary uterine inertia
- Correct calcium abnormalities if present; calcium gluconate infusion over 10-15 mins
- Correct glucose abnormalities if present
- Oxytocin if you are happy there is no obstruction
- Can repeat x3 but if not progressing after 2nd dose unlikely to
- Should see improvement in Ferguson’s reflex
- Pup within 40 mins of oxytocin
38
What are the maternal indications for surgical management?
- Primary uterine inertia
- Secondary uterine inertia non-responsive to medical management
- Maternal obstruction including uterine torsion
- Uterine rupture
- Systemically unwell bitch
39
What are the foetal indications for surgical management?
- Foetal distress on ultrasound (protracted medical management decreased survival rates)
- Oversized foetus
- Foetal malpresentation not corrected with manipulation
- *Valuable litter* - this is a controversial topic, but if an owners priority is pups prolonged medical management may be contraindicated
40
What are the 3 key areas of consideration for a caesarean section?
- Anaesthesia
- Surgical equipment and approach
- Staffing
41
What needs to be considered when using anaesthesia during a caesarean section?
- Drugs given to mum may cross the placenta and impact on pups
- Adjust timing of medications
- Check drug licensing information carefully for contraindications
- Risk of hypothermia
- Think about how you are going to resuscitate and monitor pups after delivery. This is a whole team job, and you may need to call in extra staff to help with this
42
What are the anaesthetic considerations are needed for the bitch?
- Pregnancy increases oxygen demands: pre-oxygenate prior to induction
- Higher cardiac output
- Risk of venous obstruction from gravid uterus on vena cava
- Delayed gastric emptying/lower oesophageal sphincter tone: anti-emetics/pro-kinetics/ gastroprotectants
- Hypothermia
43
Describe off license consent for c-sections
The cascade allows us to use medications in a different way to how they are described by the manufacturer. However to do so we must have owner consent
This is particularly important when using drugs in way the manufacturer lists in the drug contra-indications
Medications described as ‘not safety assessed’ or ‘can be used after a risk assessment by the veterinary surgeon’ should ideally be chosen over those stating ‘do not use’ in pregnancy.
44
Describe the steps of the anaesthetic plan for a c-section
- Pre-oxygenate
- IV line placement and fluids
- Prep if possible
- Induction
- Local anaesthetic
- Maintain and monitor
- Systemic analgesia
45
Describe pre-med for c-sections
Avoid if possible - not usually part of an anaesthesia plan but need to consider pups as well as mum. Most products are also off license in pregnancy, but some have specific contraindications.
In some cases (eg anxious bitch) you may have no choice. You should choose a drug which is reversible so any impacts on puppies can then be reversed.
46
Describe pre-oxygenation for c-sections
Tight fitting mask is preferred option – but if bitch not tolerating step down
Aiming to maximise oxygenation, stress and struggling will counteract this
Especially important in Brachycephalics
47
Describe IV fluid therapy for c-sections
Peripheral IV catheter placement
Start IVFT – aim to correct any losses before surgery where possible. Isotonic crystalloids appropriate in most cases
5ml/kg/hour then adjust dose based on blood pressure and cardiovascular examination
48
Describe pre-op prep for c-section
We usually aim to clip and prep the patient once they are asleep. In the c-section we are aiming to minimize time from induction to delivery.
If temperament allows clip the abdomen with the bitch standing or in lateral recumbency.
Perform an initial skin scrub prior to induction
49
An induction agent should have which 3 characteristics?
- Rapid onset of action
- Rapidly metabolized (minimizes impacts on pups)
- Can be titrated to effect
50
What are the two induction agents used in first opinion practice for c-sections?
Propofol
| Alfaxalone
51
Describe Propofol use for induction of c-sections
Fast onset of action, titrated to effect
Licensing states “Propofol has not been used in dogs and cats where the pregnancy is to be maintained, but been used successfully for induction prior to Caesarean section”
52
Describe Alfaxalone use for induction of c-sections
Fast onset of action, titrated to effect
Licensing states “The product has been safely used in dogs for the induction of anaesthesia prior to delivery of puppies by caesarean section”
Some studies show less pup depression with alfaxalone vs propofol
53
Why and where is local anaesthetic used in c-sections?
Local blockade can be used to minimize inhalational requirements – especially important when a pre-medicant agent has not been used
Skin/subcutis – block during prep and prior to first incision
Linea alba – block during entry to abdomen
If performing OVH – ovarian and cervical pedicle splash blocks
54
Describe the main features of maintenance and monitoring during a c-section
- Isoflurane and Sevoflurane two most widely available inhalant agents: both have no specific licensing data for use in the C-section patient
- Patient positioning is important: elevate the thorax to drop abdominal contents away from the diaphragm
- Monitoring should be as for any anaesthetized patient: ensure you have enough staff to continue monitoring during puppy resuscitation
55
When is systemic analgesia given in a c-section case?
For most surgical cases we aim to give this prior to induction, but in the C-section patient we want to minimise placental diffusion to the pups
We therefore give systemic analgesia once the puppies have been delivered. This also means from a licensing view the patient is no longer pregnant – so we only need to be aware of lactation contraindications
56
Describe the options for systemic analgesia
- NSAIDS: (meloxicam/robenacoxib off license in lactating animals, carprofen no data)
- Opioids: methadone (use not recommended in lactation) vs buprenorphine (care should be taken during lactation – will pass into milk)
- Paracetamol: human medication off license, no data to suggest milk transfer
57
What are the consequences of inadequate pain control
Inadequate pain control in the bitch will prevent nursing behaviours and increase risk of aggression towards pups – your analgesia plan is a risk:benefit assessment
58
Describe the surgical steps in a c-section
- Midline approach: Incision needs to be large enough to exteriorise the uterus
- Abdominal entry
- Exteriorise: Bring the uterine horns out of the surgical incision and pack the abdomen with damp laparotomy swabs
- Uterine incision: Incise over the uterine body and milk the pups down each horn
- Check for pups prior to closure, go from ovary to cervix twice!
- Uterine closure: 2 layer, monofilament absorbable
- Flush and close up the abdomen in 3 layers
59
What equipment is needed for immediate neonatal care?
- Box with LOTS of warmed towels at least one per expected pup plus two
- Heat pad underneath box (care re: direct heating)
- IV catheters: can be placed into umbilical veins
- Clamps (for umbilicus)
- Resuscitation drugs
60
Name some resuscitation drugs
Atropine
| Adrenaline
61
Describe recovery following a c-section
- Don't use hibiscrub to clean tears
- Don’t leave mum and pups unattended, accidents can and do happen
- Aim for discharge asap
- Pups should be noisy and looking for food. Check pups for palates and bums
- Make sure owner brings a box to the discharge appointment for the pups
62
Describe the financial side of a c-section
- Carefully document your decision making in the absence of diagnostic findings (and why you have not performed diagnostics)
- Remember your obligation is for the welfare of the bitch – a stuck puppy needs immediate attention. An inertia can be managed less intensively while owners find funds or if overnight until normal hours where a section can take place for less expense
- While emotive, euthanasia relieves suffering of the bitch and in extreme circumstances this may be your only option
- Find out your practice policies on debtors and emergency first aid BEFORE the first time you need to know
