Canine Pregnancy Flashcards
when does parturition occur after LH surge
65 d
when does parturition occur after ovulation
63 d
when does parturition occur after diestrus
57 d
when does parturition occur after 1st breeding date
57-72 d (lots of variability)
when is the fertile period
2-4d post ovulation
what do progesterone levels need to be for pregnancy maintenance
> 2ng/mL
is progesterone elevated only during pregnancy
no, progesterone is elevated
regardless of pregnant or not
what is P4 produced by
CLs
when does P4 decrease prior to parturition
24-48hrs prior
what is prolactin required for / important for
-Required for maintenance of CLs → indirectly maintain progesterone
-Important for milk production
-Pituitary origin
what is LH important for
CL maintenance
what is relaxin produced by
placenta
what hormone can we use to diagnose pregnancy in dogs
relaxin
cause of pregnancy associated anemia
-Reduction of PCV (packed cell volume) down to 32-35% (37-55% normal)
-Caused by hemodilution → increase in blood volume; not a decrease in RBCs
three physiologic changes in pregnancy
-pregnancy associated anemia
-increase in acute phase proteins
-leukocytosis without left shift
what are the three phases of pregnancy
- ovum (d2-17)
- embryo (d18-35)
- fetal (d35-birth)
what happens during phase 1 of pregnancy
◦ Fertilization in the uterine tube
◦ Embryos (blastocyst stage) descend from oviducts into uterus 10-12 days after the LH surge
◦ Trans-uterine migration occurs (d12-17)
what happens during phase 2 of pregnancy
◦ At 18-20 days post LH surge, fixation & implantation begins
◦ Implantation ends 2 days later
◦ Organogenesis of the embryo
what happens during phase 3 of pregnancy
◦ Ossification/mineralization
◦ Rapid growth period
what is the embryotoxicity critical time point
6-20 days post LH
when does the placenta develop
approx 20-22 d
what happens at marginal hematomas on placental
◦ Maternal blood hemoglobin is metabolized to uteroverdin (Embryo gets iron from here)
when can you do abdominal palpation for pregnancy dx
25-35d of pregnancy
when can you do abdominal ultrasound for pregnancy dx
d19… most often done >24d pregnancy
what is abd u/s important for
gestational ageing
when can you do abdominal rads for pregnancy dx
best results = 3-5d prior to due date
when does fetal mineralization occur
45d of pregnancy
when can you accurately detect relaxin and what happens if its too early or if there is abortion
◦ >19-21 days of pregnancy; levels peak mid-pregnancy
◦ Often measured at 24-26 days of pregnancy
◦ If too early → false negative → recheck or small litter in giant breed dog
◦ If resorptions/abortions → false positive
why do premature puppies have high mortality rate
bc no surfactant if > 2 days before due date
what happens if puppies arent born 2d post whelping date
Canine placenta cannot support fetuses >2 days past whelping date
= intra uterine fetal death
why is gestational ageing important (5)
◦ To know when they are due!
◦ Bitches that require elective c-sections (brachycephalics, singleton litters)
◦ Bitches that may require additional monitoring during whelping
◦ High risk pregnancy bitches
◦ Bitches that require progesterone supplementation to maintain pregnancy
what is the gold standard for gestational ageing
ultrasound
when fetal maturation and organ development occurs
◦ Amniotic vesicle as early as 19-21 days
◦ Heart beat 1st visible at 23-26 days
◦ Placenta becomes zonary at 29-31 days
◦ At 32 days, placental edges starts to curl inwards
◦ At 37 days, fetus is longer than zonary placenta
what are fetal and extra fetal measurements
◦ Amniotic vesicle as early as 19-21 days
◦ Heart beat 1st visible at 23-26 days
◦ Placenta becomes zonary at 29-31 days
◦ At 32 days, placental edges starts to curl inwards
◦ At 37 days, fetus is longer than zonary placenta
what happens in the last third of canine pregnancy
Last 3rd of canine pregnancy = period of rapid fetal growth – bitch should gain 25-30% of her body weight by time of whelping
◦ Should take number of fetuses, breed & age of bitch, activity level & bitch’s BCS into consideration
what type of diet should a pregnant bitch be on
-Should be on diet with increased protein, carbohydrates and minerals + increased calories
( >375kcal/cup; 400-450kcal/cup is better)
◦ Small, frequent meals → Especially if not eating well
◦ Diets made especially for growth or lactation (e.g. puppy food, high performance diet)
what should you not supplement during gestation and why
◦ Calcium
◦ Do NOT supplement with calcium during gestation → predisposes to hypocalcemia, dystocia
◦ Ca:P ratio no higher than 1.2:1; no lower than 1:1
raw diets and pregnancy
◦ Not recommended during pregnancy, especially if homemade
◦ Possibility of bacterial transmission from the GI tract to the uterus via the bloodstream → early embryonic death (EED), abortion, placentitis
◦ Should recommend consultation with veterinary nutritionist, especially if homemade
issues with diets high legume content in pregnant dogs
◦ Believed that legumes bind calcium → less useable calcium available
◦ Predisposition to hypocalcemia → during labor or post partum
housing during pregnancy (3)
◦ Should be kept away from any dogs/puppies with unknown vaccine status
◦ Should be introduced to whelping area 5-7 days prior to due date
◦ Temperature + humidity control
vaccine status during pregnancy
◦ Should not give vaccines during pregnancy → especially not modified live
◦ Ideally would be vaccinated earlier than 2 weeks prior to breeding
deworming during pregnancy
◦ Should be dewormed regularly & appropriately for pregnancy
exercise during pregnancy
◦ Should be moderate
◦ No rough housing, dog sports, etc.
drugs during pregnancy (4)
◦ Should be avoided as much as possible during pregnancy
◦ If they are necessary, all drugs should be evaluated while taking physiologic changes that occur in the pregnant bitches into account
◦ Generally short periods of time, moderate doses are better
◦ Drugs have been categorized to help determine which are “safer” to use in pregnancy
two metabolic diseases during pregnancy
◦ Gestational diabetes mellitus
◦ Pregnancy toxemia
non infectious causes of pregnancy loss
◦ Maternal disease, poor nutrition, drugs, genetic disease, aged oocytes, maternal stress, hypoluteoidism
pregnancy loss in the 1st half of pregnancy
Early embryonic death → resorptions → 1st half of pregnancy
pregnancy loss in the 2nd half of pregnancy
Abortions → birth of alive or dead fetus + placenta → 2nd half of pregnancy
◦ Stillbirths
◦ Mummification
◦ Maceration
◦ Fetuses born at this stage cannot survive long outside the uterus
gestational diabetes; progesterone, clinical signs, diagnosis
-Progesterone → insulin resistance → decreased intracellular glucose uptake → decreased intracellular glucose reserve + increase blood glucose
-Progesterone = inc. growth hormone = insulin antagonist
-Clinical signs = similar to diabetes mellitus in all dogs (PU/PD), polyphagia, weight loss
-Diagnosis = hyperglycemia + glucosuria
treatment of gestational diabetes and what happens if its untreated
Treatment should be attempted
◦ Insulin – requirement of higher doses is expected
◦ Fluid therapy
◦ Can be challenging
Untreated
◦ Larger puppies → dystocia
◦ Increased neonatal morbidity and mortality (in humans at least)
what is pregnancy toxemia associated with and when does it occur
Associated with lack of carbohydrates or alteration in carbohydrate metabolism
Occurs in late gestation
risk factors of pregnancy toxemia (5)
◦ Prolonged anorexia
◦ Inappropriate nutrition
◦ Intake of carbohydrates < what is needed
◦ Increased litter size
◦ Some form of stressor (eg. change in environment, concurrent illness)
what risk is elevated in pregnant dogs with pregnancy toxemia
Late pregnancy = ability to produce glucose
◦ Decreased/blunted response to hypoglycemia
Hypoglycemia risk is elevated
◦ Decreased ability to produce glucose
◦ Increased requirement for glucose → fetal development & growth
Persistent hypoglycemia → insulin secretion suppression → mobilization of fat + release of fatty acids + ketones
clinical signs of pregnancy toxemia
◦ Anorexia
◦ Depression
◦ Weakness
◦ Ataxia
◦ Collapse, seizures, coma
treatment of pregnancy toxemia
◦ IV glucose
◦ Correct dehydration, electrolyte
abnormalities
◦ High protein, energy rich diet ad libitum
◦ In some instances, no response to tx → pregnancy termination is required
◦ Pregnancy termination will correct the condition
◦ If mild, could respond to diet change only
diagnosis of pregnancy toxemia
◦ Hypoglycemia + ketonuria without glucosuria
options for fetal monitoring
Tocodynamometry (Whelp Wise )
◦ Detects changes in intrauterine & intra-amniotic pressures
◦ Monitors fetal viability & well-being
Ultrasound
◦ Fetal heart rate (FHR) = very good indicator of fetal stress
◦ Prolonged decelerations of FHR = fetal stress
◦ FHRs <180bpm can be associated with fetal stress; <160bpm = severe fetal distress
◦ Transient decrease in FHR during uterine contraction = normal
Radiographs
◦ Idea on fetal size (eg. 1 fetus much smaller than others)
◦ Fetal death can be identified
◦ Presence of air in the uterus or around the fetus, skull bones deformed or overlap each other,
balling of the fetus or hyperextension of the hindlimbs
what is the normal fetal HR
180-200bpm
when does fetal monitoring help
Can be done to both monitor a high-risk pregnancy or to help determine to fetal readiness for birth
behaviours with pseudopregnancy
→ Behavior can be very similar to pregnant bitches
◦ Weight gain, inappetence, nausea
◦ Mammary development, milk production
◦ “Nurse” toy, guard toys → puppy substitute?
