Canine Pregnancy Flashcards
1
Q
How can the whelping date of a bitch be determined?
A
- Gestation length:
- 57-72 days from first breeding
- 64-66 days from LH peak
- 62-64 days from ovulation
- 56-58 days from D1 of cytologic diestrus
2
Q
What occurs during early pregnancy of the bitch?
A
- Embryos reach the uterus 9-13 days after LH peak
- Transuterine migration
- No maternal recognition of pregnancy
- Since there is no cyclic release of PGF2a in the non-pregnant female, maternal recognition is not recognized in the dog
- Implantation 16-18 days after LH peak
3
Q
What is the placenta like in dogs?
A
- Zonary, endotheliochorial
- 2.5 to 7.5 cm wide band surrounds chorionic sac
- Endothelium of endometrial blood vessels are in direct contact with the chorion
- Phagocytosis of RBCs occurs at the margin of the zonary placenta
- source of maternal iron to the fetus
- marginal hematoma (hematophagous zone)
- heme is broken down to biliverdin
- 5-10% mAbs transferred in utero
- passive immunity mostly derived from colostrum
4
Q
What hormones are present during canine pregnancy?
A
- Progesterone
- CLs only source
- Similar in pregnant and non-pregnant
- Diestrus ends when concentrations decrease and remain at a level inadequate to support
- pregnancy
- <2ng/ml
- 24-48 hrs prior to parturition
- 51-82 days in the non-pregnant female
- Prolactin
- CL function dependent on luteotropic activity
- Relaxin
- specific to pregnancy
- produced by the placental unit
- Detectable at 3rd week of pregnancy
- Peaks around 40 days of pregnancy
- 4-6 ng/ml
- Detectable 4-9 weeks postpartum
- delayed sloughing of trophoblast cells during involution
- 0.5-2.0 ng/ml
- Acute Phase proteins:
- result from inflammatory response due to the invasion of the uterus by fetal tissue during implantation and placentation
- C-reactive protein and fibrinogen
- elevations seen ≥28 days post LH peak
- Fibrinogen >280-300 mg/dl consistent with pregnancy
- may be elevated due to other inflammatory conditions in non-pregnant bitches
5
Q
How is pregnancy diagnosed in bitches?
A
- Transabdominal palpation
- Palpation of chorioallantoic swellings
- Perform 30-35 days after LH peak
- 3-5cm in diameter
- After day 35 difficult to distinguish
- after day 45, palpate mineralized fetus
- Iatrogenic fetal death
- Accuracy:
- 88% for pregnancy diagnosis
- tense abdomen, obese/large dog, one pup
- 12% fetal number determination
- 88% for pregnancy diagnosis
- Transabdominal US
- Early diagnosis
- embryonic vesicle 20 days post-LH peak
- Determination of fetal number
- 38% due to fetal resorption throughout pregnancy
- Fetal viability, stress, and age
- Fetal heartbeat first seen between 22 and 29 days
- Normal fetal heartbeat > 200bpm
- Early diagnosis
- Abdominal radiographs
- Accurate during late stages of pregnancy
- after onset of fetal calcification: 45 days post-LH peak
- Determination of litter size
- number of skulls and associated vertebral columns
- Determination of fetal size in relation to maternal birth canal
- Fetal death seen as intrauterine gas pockets or misshapen fetal skeletons
- visualized within 48hrs following fetal death
- Accurate during late stages of pregnancy
- Acute Phase Proteins
- Relaxin
6
Q
What is pregnancy toxemia (ketosis)?
A
- Occurs in late gestation in females on inadequate nutrition or who cannot eat enough carbohydrates to meet energy demands because of size or number
- Associated with large litters
- Occurs in all breeds - Yorkshire Terriers and Labrador Retrievers
- Dx:
- ketonuria w/out glucosuria
- +/- decreased concentrations of blood glucose
- Clin Signs:
- anorexia
- weakness
- inability to stand
- seizures
- coma
- Tx:
- Provide nutrient dense diet
- IV dextrose
- Induction of parturition
- Termination of pregnancy or C-section
7
Q
How does parturition start?
A
- Parturition cannot occu until progesterone concentrations fall to <2ng/ml
- 24-48hrs before parturition
- Decrease in progesterone results in transient hypothermia
- 10-14hrs after drop
- Falls >1.6F or < 99F then returns to normal prior to parturition
- Labor 8-24 hrs later
- Monitor temp 2-4 times daily starting on day 54 after breeding
8
Q
What happens during stage 1 of whelping?
A
- 6-12 hrs
- Synchronous uterine contractions leading to cervical dilation
- Placental separation
- Green-black vulvar discharge
- Clinical signs
- anorexia
- Restlessness
- apprehension
- panting
- shivering
- vomiting
- obsessive nesting
- +/- seclusion
9
Q
What happens in stage 2 and 3 of whelping
A
- Begins w/ full dilation of the cervix
- strong uterine contractions and visible abdominal straining
- Puppies delivered every 30-60 minutes
- Order typically alternates between uterine horns
- Ends with expulsion of the fetus(es) and fetal membranes
- fetal membranes are expelled with the puppies or 5-15 minutes later
- Ensure no fetal membranes are retained
- Complete w/in 6 hrs
10
Q
What qualifies as dystocia during whelping?
A
- 5% of whelpings
- Prolonged gestational length: >65 days post-ovulation, >60 days D1
- Failure to deliver a pup w/in 36hrs of serum progesterone <2ng/ml
- Failure to deliver a pup w/in 24hrs of retal temp <99F
- Stage 1 labor >12hrs
- Vigorous stage 2 labor fails to produce a pup w/in 30 minutes
- weak or intermittent stage 2 labor fails to produce the first pup w/in 4 hrs
- Vulvar discharge present for 2hrs w/out delivery of the first pup
- No further pups delivered w/in 2hrs of the previous pup
11
Q
What are maternal and fetal causes of dystocia?
A
- Maternal:
- Uterine inertia
- Inadequate birth canal size
- Obstruction of the birth canal
- Decreased abdominal press
- weakened abdominal musculature
- Ruptured diaphragm
- Obesity
- Fetal
- Oversize
- feto-maternal disproportion
- single pup
- Abnormal orientation
- Oversize
12
Q
What is uterine inertia and why does it cause dystocia?
A
- Primary uterine inertia
- lack of normal, sequential uterin contractions resulting in failure to expel fetuses
- Complete when stage 1 fails to proceed to stage 2
- Partial parturition begins normally but contractions stop before fetal expulsion occurs
- Unknown etiology:
- Inherited breed predisposition
- Overstretching of uterine musculature
- Inadequate uterine stimulation
- Hypocalcemia, decreased oxytocin release
- Systemic disease, obesity, uterine torsion
- Tx:
- C-section
- Many do not respond to medical therapy
- measure serum calcium
- Prognosis: good to grave
- Secondary Uterine Inertia:
- occurs after prolonged uterine contractions and maternal exhaustion ensues
- Fail to respond to Oxytocin
13
Q
How is Dystocia diagnosed?
A
- Confirm pregnancy
- abdominal palpation
- Digital vaginal examination
- Radiography
- Ultrasonography
- Confirm gestational length and term
- progesterone < 2ng/ml
- confirm labor has begun and is not progressing normally
- Obstetrical exam to determine cause of dystocia and detect fetal and/or maternal compromise
14
Q
What are the possible treatments for Dysocia?
A
- Vaginal manipulation
- Medical therapy
- C-section
15
Q
When is vaginal manipulation used during dystocia?
A
- Pup lodged in birth canal
- slight oversize
- correctable malposition
- uterine inertia prevents delivery of the final pup
- Birth canal size may prevent manipulative attempts
- Use plenty of lubrication
- 2 fingers to gently perform manipulation
- Do NOT grasp distal extremities or tail
- Concurrent abdominal palpation may aid in manipulative efforts
- Puppies not protruding or failure to easily correct should proceed to C-section
