Whelping and Dystocia Flashcards
Dystocia
- difficult birth
- Life threatening for mother and off spring
- 5% of all pregnancies
- Much more frequent in brachycephalic breeds
- Breeding soundness exam should include consultation regarding delivery
- General health and body condition are important factors
Screening for dystocia over the phone
- Determine reason for concern
- Obtain history and prior pregnancies
- Determine if events are normal
- Best to see patient early if any doubt, especially if concern is voiced by an experienced breeder
Determining delivery date based on breeding date
57-72 days
- 52-74 for feline
- Not super reliable
How far past LH surge is delivery?
65 +/- days
How far past ovulation is delivery?
63 +/- days
How far past fertilization is delivery?
60 +/- days
If using vaginal cytology, how far past D1 (???) is delivery?
57 days
How to determine delivery date in felines
- Induced ovulator so hormonal timing not very useful
- Must rely on clinical signs of labor
Which hormones cause onset of labor?
- Prostaglandin F2 alpha and fetal cortisol
Relative gestation length in small vs big litters?
- Small litters have prolonged gestation and large litters may shorten gestation in dogs
- Cat gestation length not affected by litter size
What level is progesterone above to maintain pregnancy during late gestation?
- Above 5 ng/mL
How does prostaglandin F2 alpha induce labor?
- Luteolytic so it drops progesterone to less than 2 ng/mL
How soon after progesterone drops to <2 ng/mL do you expect to see signs of labor?
8-24 hours
What will happen to a female dog’s temperature as progesterone drops?
- Her temperature will drop, because progesterone is thermogenic
- Monitor rectal temperature twice a day at least
Radiographic indicators of gestation length
- Skull and spine observed at 45 days
What can you use radiographs at time of labor for?
- Number of fetuses remaining
- Size of fetuses
- Shape
- Position and presentation
Which method is best for assessing fetal stress?
- Ultrasound
What signals fetal stress best on ultrasound?
- Low heart rate
- <150 is concerning
- Less than 100 means death is imminent
Normal fetal heart rate
- 2 times that of the dam
- 180-220+ bpm
Home monitoring of fetuses and pregnancy
- Fetal heart rate with Doppler
- Hard to distinguish fetuses over time
- Tocodynamometer
Tocodynamometer
- Measures pressures associated with contraction of the uterus
- Helps identify beginning of labor and progression either normal or abnormal
Stage 1 labor signs
- Panting, nervous, restless, nesting behavior, vomiting
How long does Stage 1 labor last?
6-12 hours or longer with a nervous first litter mother
What can cause a long stage 1 labor?
Uterine inertia
- Examine bitch or queen if any doubt
Stage 2 labor signs
- Contraction of uterus with visible abdominal straining
- Green or clear fetal fluids passed
- Amniotic sac may be visible
When should first puppy or kitten appear after stage 2 starts?
4 hours
Once fetus is visible at the caudal pelvic canal, how soon until it should be delivered?
- 20 minutes
How long until litter is fully delivered?
- 12 hours
- DO NOT ALLOW LABOR TO CONTINUE BEYOND 24 hours
Large amounts of bright red fluid during labor/delivery - normal or not?
- NOT
Fetal membranes - when can you see them?
- Only shortly before delivery and after delivery
- Therefore check the yard for a pup if the bitch went outside unsupervised
Stage 3 labor
- Passing placenta
- Shortening of the uterus
- Rest period 1-2 hours
Complete primary inertia
- Normal birth canal
- No fetuses delivered
What can cause complete primary inertia?
- Small litter and inadequate stimulation
- Large litter and over distended uterus
- Systemic disease
- Electrolyte imbalance
- Fatty infiltration of the uterus
- Uterine age
- Unknown
Partial primary inertia
- Normal birth canal
- Some fetuses born
- Uterus becomes fatigued
What can cause partial primary inertia?
- Same as in complete inertia
Secondary inertia
- uterus exhausted due to obstruction to passage of fetus
What can cause obstruction?
- Narrow pelvis
- Large fetus
- Abnormal presentation
- Fetus malformation
- Vaginal septum or extensive stricture
How do you treat complete primary uterine inertia?
- C-section only
How do you treat partial primary inertia or secondary inertia?
- Surgery MAY be needed with partial primary inertia and secondary
- Surgery is definitely needed if >4 fetuses remain
- Medical management can work ~25% of the time
What to do during examination of the mother for dystocia?
- Keep with puppies or kittens
- Look for signs of active delivery
- Evaluate general condition
- Radiographs
- Blood tests for PCV, TP, Calcium, and glucose
- Ultrasound of fetuses to check for stress
Vaginal examination
- Check for fluids and relaxation of vagina
- Use copious amounts of sterile lubricant
- Check for presence of a fetus in or at the pelvic inlet
- Assist normal delivery by gentle traction on head or pelvis
- Try to extend legs if possible
Normal presentation of fetuses
- Can be anterior or posterior with legs out or legs tucked under
Abnormal presentations
- Head folded back or folded under
- going out sideways
How to reposition fetus for delivery?
- Place fetus in normal position
- Rotate along along axis slightly to help pass through pelvic canal
- Be cautious of instruments and DO NOT USE OBSTETRICAL clamps
- Lift and rotate the mother to help bring fetus
Ferguson reflex
- Stimulate by stretching the vagina
- Body will start pushing in response
- This is what you can do if there is a dystocia
Where to grab the fetus?
- Behind jaw bones or behind the hocks
Steps for dystocia
- Determine if in Stage I labor or in Stage II uterine inertia/dystocia
- IV fluids to support blood pressure
- 10% glucose for hypoglycemia
- 10% calcium gluconate for hypocalcemia (SC is safer for heart)
- Low dose oxytocin following fluids, glucose, and calcium
Dosing of oxytocin
- Initial dose is 0.25 to 0.5 units per bitch or queen
- Maximum 2 units per bitch
- Maximum 3 doses
C-section essentials
- Anesthesia, rapid sx site preparation, and a team that can work with newborns
- Precise surgery is important to avoid post-op hemorrhage
- Oxytocin may be given to assist uterine involution and help control bleeding
Will OVH affect milk production or mothering instinct?
- No
Drugs for C-section
- Pre-anesthesia oxygenation
- Glycopyrrolate pre-anesthetic
- Propofol for induction
- Isoflurane or sevoflurane
- Local anesthetic at incision site
- Epidurals
- Oxytocin to promote uterine involution
Why give glycopyrrolate during C-section?
- Vagal stimulation with uterine manipulation is expected
- Doesn’t cross the pracenta as much as atropine
Why give propofol for anesthesia induction?
- Rapid redistribution with minimal effect on the fetus
Why no atropine for c-section?
- Relaxes maternal esophageal sphincter and can lead to esophagitis
Why no dexmedetomidine or xylazine for c-section?
- Neonatal and maternal cardio-depressant
Why no opioids for c-section?
- Neonatal respiratory depression
- MAY be able to give during pre-anesthetic if you reverse with naloxone during neonatal resuscitation
Why no phenothiazine tranquilizers, ketamine, barbiturates for c-section?
- Neonatal overall depression
Why no nitrous oxide for c-section?
- Rapid transfer across placenta
- neonatal diffusion hypoxia
Why no NSAIDs for c-section?
- Impairs neonatal nephron development and hepatic function, although a single dose MIGHT be given post-surgically
Mask induction with iso or sevo in c-section
- Works but greater hypoxia (and stress!!!) than with pre-oxygenation and propofol
What medications can be given to stop uterine contraction?
- Terbutaline
- Tocolytic
Regumate
- Supplemented progesterone if there is low progesterone
What to do in case of a dystocia?
- Brucella testing
- Measure serum progesterone
