THERAPEUTIC MANAGEMENT OF DYSTOCIA IN CANINES
Any impediments, irrespective of their nature, which prevent the progress of fetal expulsion from the uterus, through the maternal birth canal, after completion of gestation, constitutes – “DYSTOCIA”.
In order to understand the various possible factors, which can lead to such a situation, it is necessary to outline the events in “Normal Parturition”.
Late Pregnancy--------> Increase in PG levels--------> Decrease blood flow to corpus luteum
--------> Luteal degeneration ------> Sharp decline in progesterone -----> Increase in pituitary prolactin -------> Milk secretion + nesting (Panting, restless, vomition)-----> Drop in body temp. from 101.8F to 99F or lower24-48h before partus ----------> First stage ------> Uterine contractions (mild, asynchronous).
Intense uterine contractions
Dilatation of cervix
Clear/White vaginal discharge
Second Stage Labour:
- Beings within 24 h of temperature drop.
- Strong abdominal contractions.
- Expulsion of pups.
- Head first, occasionally feet first or even breech presentation.
- Each pup followed by individual placenta.
- Pups born in succession at intervals of minutes/1hour.
- Intervals greater than 20 minutes, contractions decrease in frequency/intensity.
- Allowing already born pups to nurse between deliveries – stimulates uterine contractions.
- Full bladder/rectum slow down the process. Leash walking – allowing urination/defection hastens the process.
- During interludes – allow some water to prevent dehydration and some source of sugar to replace the depleted energy resources.
- Total duration of second stage labour could be several minutes to several hours.
- Uterine contractions stop after the expulsion of last pup and placenta.
Whelping – When?
A. First day of mating:
Range 57 to 72 days
B. Monitor LH surge:
65 ± 1 day
C. Monitor ovulation:
63 ± 1 day
Parturient Complications
- Primary uterine inertia
- Pre-eclampsia/eclampsia (Hypocalcemia)
- Pelvic obstruction (Anatomical defects/fetal oversize)
- Premature placental separation
- Secondary uterine inertia
- Uterine torsion/rupture
- Fetal distress
Non emergencies
Due date reached? But:
- No decrease in body temperature.
- No signs of first stage labour (Generally uterine contractions/cervical dilatation must begin within 12 to 18 hours after body temperature decrease).
Emergencies
a.
6 to 8 hours after first stage – failure to progress to second stage
Obstruction
b.
Straining for more than 20 minutes, weak intermittent abdominal contractions for about 60 minutes. No pups born.
Obstruction
c.
No pups born, thick, black-green discharge
Premature placental separation
d.
Heavy persistent flow of fresh blood from vulva
Haemorrhage/uterine rupture
e.
Muscle weakness, spasm, tremors, muscles rigid
Uterine inertia
f.
More than 60 minutes between delivery of pups; no further signs of active labour; pups still present
Uterine inertia
g.
Evidence of intense abdominal pain, symptoms of shock – pale mucosa, sudden drop in body temperature (below 99F); collapse
Uterine torsion/ rupture/massive haemorrhage
Questionnaire?
Age
Breed
Reproductive history (previous litters, previous caesarean section)
Previous chronic Medical conditions
Preovulatory LH peak
Serum progesterone
Last feed and drink
Vomition
Urination/defecation
Color of vaginal discharge
Whether oxytocin has been given?
Overdue Patient
Possible causes
Late mating
Inaccurate information/calculation
Primary uterine inertia
Non-Pregnancy/resorption
Investigations
Mating date
Abdominal palpation
Fetal heart beats
Radiography – pups visible, viability unknown; bones in stomach of patient delivery and eating of pups.
Ultrasonography
Serum progesterone levels higher than 2mg/ml – incomplete gestation.
Therapy
If pups are viable, give more time. Condition of vagina – dry and tight – body temperature suggestive.
Dead pups – caesarean section, oxytocin may be tried – but likely to fail.
In primary uterine inertia (temperature fall has occurred more than 48 hour earlier but no signs of labour) or evidence of placental separation. Try oxytocin, but caesarean section is more successful.
Haemorrhagic discharge at term (no signs of labour):
Possible causes
Primary inertia with at least one fetal death.
Placental separation
Aged pet with only one pup.
Death of all fetuses in mid to late pregnancy followed by haematic mummification.
Cause unknown, but pups die at different development stages.
Investigation
Palpation
Ausculation
Radiography
Ultrasonography
Therapy: Caesarean section/hysterectomy
Non Productive Straining : Second stage labour has commenced, patient exhibits labour of reasonable intensity, no pups born for more than sixty minutes (First pup may survive upto 6 hours after onset of straining, but subsequent ones die after about 2 hours).
Possible Causes
First pup too large (small litter)
Fetal monster
Ventral flexion of nose – poll engages pelvic inlet.
Lateral deviation of head/neck.
Pup not able to get up to inlet level, bitch with pendulous abdomen.
Dead pup.
Pup in vagina, does not progress further due to large size (Small vagina).
Posterior presentation.
Straining not intense.
Vaginal tumor/polyp.
Pelvic exostosis (previous fracture).
Congenital vaginal stenosis.
Investigation
Digital exploration of vagina
Vagina relaxed and moist, but no pup present. Manipulation of caudal abdomen may make palpation easy.
Fluid filled amnion in vagina.
Part of pup in vagina.
Radiology/ultrasonograpy – viability and number of pups.
Therapy
If nothing felt in the vagina – caesarean section.
Amnion palpable in vagina – lift the fetus trans-abdominally and stimulate dorsal vaginal wall to induce uterine contractions.
Vaginal occlusion/stenosis/pelvic exostosis/tumor – caesarean section
Fetal malposition – obstetrical manipulation
Patient with some pups born; restless/larger litter expected
Possible causes
Pup in cranial vagina causing no contractions.
Secondary uterine inertia
Normal rest between pups
No more pups.
Investigation
Digital exploration per vaginum
Bimanual palpation, involuting uterus quite turgid and can be mistaken for a pup.
Radiography
Ultrasonography
Therapy
Pups present and no discharge – oxytocin
Pups present and vaginal discharge is suggestive of placental breakdown – consider immediate caesarean section.
Oxytocin Therapy
Oxytocin leads to rhythmic contractions.
Although it has short half life, contractions induced are powerful.
Initially used in small doses – 5 I.U.
If there is no effect after 10 to 20 minutes, repeat same or larger dose.
If one pup is born after oxytocin, it may be necessary to repeat for other pups.
If large number of pups are yet to be born, consider caesarean section.
Contraindicated in obstructive dystocia.
Obstetrical Manipulation
Failure of labour to progress is generally caused by one or two fetuses causing obstruction in birth canal.
Oversized fetus
Fetal malposition
Two fetuses presented simultaneously
Intervention
Fingers are the best and safest instruments.
Whelping forceps – use sponge over teeth.
Ensure asepsis as far as possible.
Finger manipulation – pushing the fetus caudally is important.
Depending upon the availability, head or hips are grabbed between fingers.
Drying of vagina is avoided by using a water soluble lubricant.
If a pup appears to be stuck, slight rotation may assist delivery.
Traction should be applied when the dam is straining.
When forceps is used – ensure avoiding vaginal damage, compression of fetus (particularly skull) and amputation of extremities.
In case no progress is made after 15 minutes, vagina gets traumatized, dam is distressed, there is fetal distress (heart rate less than 150 BPM) or many pups are yet to be born – consider caesarean section.
Calcium Therapy
For proper function and response, neuromuscular tissue depends upon a proper balance of electrolytes. Uterine contractions depend upon adequate calcium levels. When calcium metabolism stands compromised (inadequate diet, extended period of labour) – depletion of serum calcium could interfere with uterine contractions. Grossly lower levels may lead to life threatening complications, Tetany and Seizures.
Monitor calcium levels.
Recognize clinical symptoms.
Administer calcium S/C – I/V may be dangerous (Cardiac arrhythmia/sudden death).
I/V administration recommended only in cases with life threatening symptoms of hypocalcemia (Muscle spasm, nuscle rigidity, seizures, convulsions).
I/V fluid therapy if excessive vomiting/dehydration.
I/V fluid therapy must for cases of caesarean section – to cambat hypertension.
Nervous Inhibition of Labour
The patient is either in first or second stage of labour, but does not settle to whelp.
Possible causes
Unfamiliar place
Introduction to whelping box too close to term.
Absence of owner – Presence of strangers.
Remedy
Allow the patient to whelp where she wants (inconvenience)
Ensure Owner’s presence until whelping is over.