Reproductive & Neonatal Emergencies Flashcards
What is the duration of proestrus?
6-11 days (average 9)
What is the duration of estrus?
5-9 days with wide variability
What is the duration of diestrus?
- 56-58 days in the pregnant female
- 60-100 days in the non pregnant female
What is the duration of anestrus?
- In the pregnant female, begins with whelping and ends when proestrus begins
- Not as easily detectable in non pregnant females (approx 4-5 months)
In what order is the reproductive cycle?
Proestrus –> Estrus –> Diestrus –> Anestrus –> Proestrus
PEDA
What marks proestrus?
- Male is attracted to female but female does not allow mating
- Estrogen dominates
What marks estrus?
- “Heat”: female allows males to mount
- Progesterone dominates
What marks diestrus?
- Begins when female no longer allows breeding
- Progesterone dominant
- Prolactin increases in latter portion regardless of pregnancy
What marks anestrus?
- Surge of LH
- FSH increases
- Estrogen fluctuates
- Progesterone low
What is the gestation length of dogs?
55-72 days (average 63)
What is the gestation length of cats?
62-72 days (average in 64)
How many heat cycles per year does the dog have?
2 per year, lasting up to 18 days per cycle
How many heat cycles per year does the cat have?
1-3 weeks, lasting 1-7 days (seasonally polyestrus)
At what gestation date are fetal HB detected?
~ day 25
At what gestation date can fetal skeletons be seen on radiographs?
~ day 45-50
Parturition will begin with 24 hours when plasma progesterone levels are ___?
<2ng/ml
What maintains pregnancy?
Progesterone from the corpus luteum
What determines the onset of parturition?
The fetus. The fetal pituitary gland secretes ACTH which sets off a chain of reactions in which oxytocin is released and causes a positive feedback effect on uterine contractions
What does Stage 1 of parturition entail?
- Changes often go unnoticed
- Nesting, panting, restlessness
- Uterine contractions begin (NOT visible)
- Cervix dilates
- Lasts 6 - 24 hours
A drop in temp of ____ correlates with a drop in progesterone in stage 1 of parturition
<100F
What does Stage 2 of parturition entail?
- “True labor”
- Visible contractions
- Rupture of clear fluid prior to delivery of each neonate
- May also be green mucoid discharge before, during, and after - “lochia” (indicates placental separation)
Once clear fluid has been seen in Stage 2 of labor, what should the time of delivery be for the first fetus?
< 1 hr
How frequently should a fetus be birthed during Stage 2 of labor?
q10-60 minutes but can extend to 3 hours
What does Stage 3 of parturition entail?
- Passing the placenta but usually occurs in stage 2
- Ensure all placentas have passed
Is the posterior presentation of fetuses in littered animals normal or abnormal?
Normal
What is the most common cause of maternal dystocia?
Uterine inertia
What is the most common cause of fetal dystocia?
Malposition
What problem is most commonly seen with single pup pregnancies?
Oversize
How does intrauterine fetal death predispose to dystocia?
Increases the chance of malpresentation because of failure to rotate and extend head and legs
What is primary uterine inertia?
- Uterus fails to contract with sufficient force due to inherited breed related causes
- Failure of the muscles to respond to hormonal stimuli, or failure of actual release of hormonal stimuli
What is partial primary uterine inertia?
Parturition is initiated and 1 or more fetuses is expelled but subsequently fails to deliver remaining fetuses due to myometrial fatigue
What is secondary uterine inertia?
Uterus fails to contract with sufficient force due to exhaustion, lyte disturbance, hypoglycemia, dehydration
When do still birth rates rise?
When dystocia is allowed to continue for >4.5-6h from onset of stage 2 in dog
Dams should present to ER if:
- Fails to initiate labor at term
- Fails to progress to stage 2 within 24-36 hours after a drop in T or progesterone
- Fails to deliver all fetuses in a timely manner (1st fetus should appear within 1 hour of active labor or within 2 hours of intermittent labor)
- Fetal distress or stillbirths
- Maternal distress
- Resting >4 hours between fetuses without contractions
- Weak/absent contractions for >2 hours
- Fetus in vulva >15 minutes
Why does achondroplasia increase the incidence of dystocia by 50%?
The condition causes a reduction in dimension from sacrum to pubic bone and thus reduces the pelvic canal
What are other factors that can increase the chance of dystocia?
- Obesity
- Stress (catecholamine release in the dam can put the fetuses at increased risk by reducing uterine blood flow)
What indicates fetal death on radiographs?
- Intrafetal gas
- Overlapping bones of skull
- Spinal collapse due to loss of muscular support
Why are small/single fetus litters believed to increase the risk of primary uterine intertia?
There is not enough hormonal stimulation from the fetus to initate parturition
How many doses of oxytocin should be given before c-section is indicated?
2 - if the second fails, should go to emergency c-section
What can high doses of oxytocin cause?
- Tetanic uterine contractions
- Impair placental blood flow and fetal oxygen supply
- Do NOT result in expulsion of fetus
- Can result in uterine tears and placental separation
Why is RSI indicated for c-section?
- Patient is unlikely to be fasted. High aspiration risk
Does progesterone increase or decrease the MAC of an inhalent?
Decreases
Is there an advantage to maintaining the dam on propofol instead of gas?
No, it forces the neonates to metabolize rather than exhaling
Is blood flow to the uterus autoregulated?
No, uterine perfusion depends on BP from the rest of the body. Hypotension is problematic when the patient is put in dorsal
What effect does ketamine have on neonates?
Major depressant effects
Which drugs appear to have minimal transmission into milk?
- Oxymorphone
- Hydromorphone
- NSAIDs
What is the APGAR scoring system?
- A: appearance
- P: pulse rate
- G: grimace
- A: activity
- R: respiratory effort
- 7-10 = not in distress
- 0-3= severe distress, grave prognosis
How should the neonate be rubbed to stimulate breathing?
Rubbing should be directed toward genital and umbilical regions to activate a reflex that stimulates breathing
Why is doxapram no longer reccommended?
- Increases cerebral oxygen demand
- Decreases cerebral blood flow
- Decreases cerebral oxygen delivery
Can neonates be given atropine?
Avoid - it is unlikely to be of benefit due to neonate lack of full cardiac autonomic development
What should the environmental temperature be for neonates?
85-90F for the first 5-8 days
Why is it important to keep the neonate warm?
If hypothermia develops, they generally stop eating due to inability to digest food, and ileus. HR slows and can lead to CV collapse. Resp function can also deteriorate
If a type A queen + type B tom have a type B kitten, what can happen?
The risk of death is not as high because the mother’s antibodies won’t have as strong of an action
If a Type B queen + Type A tom make a Type A or AB kitten, what can happen?
The mother’s strong anti-A antibodies will be passed to the kitten in the colustrum and peracute death can occur since the mother’s antibodies will attack the kitten RBC
What can tail tip necrosis in a kitten indicate?
Feline neonatal isoerythrolysis
Why is hypoglycemia common in the neonate?
- Limited glycogen stores
- Immature liver function
- Minimal fat
- Increased glucose demands
Pyometra occurs secondary to___?
Cystic endometrial hyperplasia
When does pyometra generally develop?
- Within 3 months after estrus
- Progesterone level is high
What is the most common microorganism to cause pyometra?
E. coli
Why can PU/PD develop in pyometra?
It is secondary to nephrogenic DI - E. coli blocks the action of ADH on the collecting ducts and interferes with Na and Cl absorption in the loop of Henle
Why should cystos be avoided in pyometra?
It could release E. coli, which can produce an endotoxin upon bacterial death that can result in endotoxemia –> severe shock reaction and death
What is endometritis?
- An infection of the uterus that unlike pyo, occurs post partum when progesterone levels are LOW
- Clinical signs similar
- Normal lochia should not be odorous - if so, suspect metritis
- Often responds well to medical therapy due to the decrease in progesterone production
What is galactostasis?
Impaction of milk
What antibiotics should be avoided in the lactating dam?
Chloramphenicol, aminoglycosides, and tetracyclines
What is uterine torsion?
The rotation of the uterus by more than 45 degrees around the long axis
What is uterine prolapse?
- The protrusion of the uterus through the cervix
- Rare
- More common in cats
What is eclampsia?
- When hypocalcemia occurs secondary to pregnancy
- Uncommon in cats
- Usually occurs 2-3 weeks post delivery
Should a dam be pre-treated with calcium supplements during pregnancy to avoid eclampsia?
No, it creates an increased risk of post partum eclampsia because the supplmentation results in reduced PTH activity (regulates calcium levels in blood by increasing levels when they are too low)
How can alkalosis lead to eclampsia?
Alkalosis increases the protein bound fraction of Ca, thereby decreasing the ionized fraction of Ca available
When are clinical signs of eclampsia usually seen?
<0.75mmol/L
Can Calcium Gluconate go SC?
Yes if mixed 50/50 with saline
What causes benign prostatic hyperplasia?
A metabolite of testosterone (5-dihydrotestosterone) reaches the prostate in extremely high concentrations and promotes the accelerated growth of prostate cells
What is the most common micororganism to cause bacterial prostatisis?
E. coli
What antibiotics can cross the blood-prostate barrier?
- Potentiated penicillins
- Enro
- TMS
- 3rd generation cephalosporins
What is the most common prostatic neoplasia?
Adenocarcinoma
What is epididymitis?
- Inflammation of the long coiled tube attached to the upper part of each testicle
- More common in younger dogs
Urethral prolapse is most often seen in what demographic?
Young brachycephalics
What can cause vaginal prolapse?
An exaggerated response of vaginal mucosa to estrogen that is normally present
