2. Canine Pregnancy Flashcards
when does parturition occur relative to:
LH surge
ovulation
cytological diestrus
first breeding
*65 days (+/- 1 day) after LH surge
*63 days (+/-1 day) after ovulation
*57 days after cytological diestrus
*57-72 days from 1st breeding date (lots of variability)
what is the best date to use to time parturition?
ovulation date
-breeding dates are much harder to use
fertile period is when compared to ovlation?
2-4 days post ovulation
Canine gestation =
= 63 days +/- 1 day from ovulation
* 63days=9weeks
is progesterone in the bitch only elevated is she is pregnant? what is this hormone produced by?
Important!!!àprogesterone is elevated regardless of pregnant or not
◦ Produced by the CLs
when does progesterone start to decrease relative to parturition?
◦ Decreases to baseline 24-48 hours prior to parturition
what level of progesterone is required for pregnancy maintenance?
> 2ng/ml for maintenance
what are the hormones of pregnancy?
-progesterone
-prolactin
-LH
-Relaxin
-Estrogen
purpose of prolactin during pregnancy and otherwise?
◦ Required for maintenance of CLs > indirectly maintain progesterone
> 35 days until term
◦ Important for milk production
◦ Pituitary origin
purpose of prolactin during pregnancy and otherwise?
◦ Required for maintenance of CLs > indirectly maintain progesterone
> starts to be produced 35 days until term
◦ Important for milk production
◦ Pituitary origin
purpose of LH during pregnancy
◦ Important for CL maintenance
purpose of relaxin during pregnancy? how is it produced? when is it present and how can we take advantage of this?
◦ Only hormone that is different in pregnancy vs non pregnancy
◦ Produced by the placenta
◦ Can be used to diagnose pregnancy
how does estrogen change during the course of pregenancy?
◦ Drops following peak in estrus
◦ Remains low until just prior to whelping
physiologic systems affected during pregnancy
Many systems affected
* Renal
* Cardiovascular
* Digestive
* Hepatobiliary
* Hematologic
how severe can pregnancy associated anemia be? what is it caused by?
◦ Reduction of PCV (packed cell volume) by up to 30%
◦ Actually caused by hemodilution > increase in blood volume; not a decrease in RBCs
> normal change that occurs virtually all pregnant bitches
what responses do we see in WBCs and acute phase proteins that are believed to be a response to the feto-placental unit?
*Increase in acute phase proteins
*Leukocytosis w/o L shift – starts @ implantation
Phases of pregnancy and their timing relative to LH surge
Can be divided into 3 sections:
- Fertilization + early embryo (fertilization => d20-22 post LH)
- Late embryo to fetal ossification/calcification (d20-22 => 40-42d post LH)
- Fetus to parturition (d40-42 post LH => parturition)
what occurs during the fertilization and early embryo stage of pregnancy?
-Fertilization
-Embryos (blastocyst stage) descend from oviducts into uterus 10-12 days after the LH surge
-Trans-uterine migration occurs
-At 18-20 days post LH surge, implantation begins
-Implantation ends 2 days later
what occurs during the late embryo to fetal ossification/calcification stage of pregnancy?
Start of fetal development; organogenesis
what occurs during the fetus to parturition stage of pregnancy?
Ossification/mineralization
Rapid growth period
during what stage of pregnancy should we be especially careful about exposing the bitch to toxins
Embryotoxicity critical time point:
6-20 days post-LH
when does the canine placenta develop
Placenta develops @ approx. 20-22 days
what kind of placenta do dogs have? what are its characteristics for its different parts?
Endotheliochorial zonary placentation (circumferential)
Marginal hematomas
◦ Present at zonary band
◦ Maternal blood hemoglobin is metabolized to uteroverdin
◦ Embryo gets iron from here
methods of pregnancy diagnosis?
Abdominal palpation
Abdominal ultrasound
Abdominal radiographs
Relaxin
what time is best to diagnose pregnancy via abdominal palpation and why?
day 25-35
before this, too small
after this, the uterus will just feel like an enlarged structure as apposed to palpating distinct circular masses
when during pregnancy can we use abdominal ultrasound for diagnosis? pros and cons?
◦ Day 19
◦ Most often done >24 days of pregnancy
◦ Important for gestational ageing; only gives estimate of fetal number
◦ Not as accurate for ageing or fetal number when done @ >37 days (fetuses too big for screen)
◦ Fetal maturation
◦ Assessment of fetal viability
when are radiographs useful for pregnancy diagnosis? pros and cons?
◦ 45 days of pregnancy = mineralization
◦ <45 days of pregnancy > soft tissue density in caudo-ventral abdomen
◦ Can’t distinguish from other causes of uterine enlargement (eg. pyometra)
◦ Fetal count & size
◦ Not accurate for gestational ageing
◦ Best results > 3-5 days prior to due date