Pregnancy failure/ problems in small animal

• What is conception failure?

  Not getting pregnant.
• What is resorption?

  Loss of the embryo
• What is abortion?

  Loss and expulsion of the fetus.
• What are stillbirths?

  Expulsion of term but dead fetus
• Causes of conception failure in the bitch

  Inappropriate timing of mating.

  Male factor infertility.

  Abnormal mating

  Mating-induced endometritis (a consequence of CEH)

  Abnormal uterine environment (a consequence of CEH).
• Causes of conception failure in the Queen

  Inadequate mating, inappropriate time.

  Male factor infertility

  Abnormal mating

  Abnormal uterine environment (less common as lower exposure to progesterone that in bitches because most cycles are anovulatory).
• Mating induced endometritis

  CEH + commensal bacteria.

  Some of these bitches respond to post-mating antibiotic - 5 days of potentiated amoxicillin starting on the last day of mating.

  Challenges with this relate to breeder misunderstanding of antibiotic use, and inappropriate antimicrobial stewardship.

  Should only be considered in properly diagnosed cases of CEH.
• Abnormal uterine environment in bitches

  Bitches with CEH are more likely to develop mating-induced endometritis

  Mating induced endometritis which does not resolve and persists into the (pregnant) luteal phase may result in pregnancy failure - these dogs reabsorb the entire litter in the early luteal phase.
• Embryonic resorption

  May be spontaneous isolated resorption:

  • Resorption of one of the embryos (with continuation of the pregnancy) is seen in 10% of pregnancies.
  • Possibly to reduce abnormal embryos or embryo number.
  • Does not appear to be infectious.

  Those who have a bigger litter are more likely to have a resorption, think this is based on the size of the placenta and the availability of the placenta to the embryos.
• Diagnosing approach to resorption in the bitch

  Most cases should be examined assuming an infectious cause:

  • Send unfrozen fetus and membranes for investigation.
  • Collect swabs of discharge for PCR.
  • Collect serum to evaluate rising antibody titre.
• Infectious causes of resorption/abortion in the Bitch

  Canine Herpes virus:

  • Venereal pathogen
  • Viral recrudescence at subsequent pregnancies.

  Brucella canis

  Canine parvovirus

  Canine adenovirus

  Canine distemper virus.
• Canine herpes virus in Bitches

  A known venereal pathogen causing vesicular lesions in the genital tract of dogs and bitches.

  Appears to be increasingly common but no studies on the prevalence in the UK.

  In bitches it may cause resorption, abortion, stillbirths; depending on when the infection occurs.

  Infection can be venereally or via the respiratory tract.

  A vaccine is available (Eurican Herpes) for bitches and is given twice during pregnancy to protect the litter.
• Diagnosis of canine herpes virus

  Serology:

  • Demonstrate exposure not infection.

  Pathology:

  • Kidneys, liver, lungs, placenta.

  Virus isolation:

  • Specific
  • Refrigerate and submit within 24 hours.
• Canine herpes virus signs in neonates (<3 weeks)

  Acutely fatal disease

  Sudden death

  Heamorrhage

  Vomiting/ diarrhoea

  Weight loss and failure to suck (fading puppy)

  Constant complaining

  Neurological signs

  Ocular disorders.
• Non-infectious causes of resorption/absorption

  Abnormal uterine environment

  Fetal abnormalities (likely based on other species but not well investigated in dogs).

  Low progesterone (GSD breeds).

  • However progesterine will decline after pregnancy loss so is the fall of progesterone the cause or effect.
• What are the side effects of using Progestogens?

  Increase the incidence of pyometra

  Result foetal abnormalities.

  Impair or delay parturition.

  Careful use of oral progesterone (Altrenogest) is used in some cases

  • Can cause abnormalities in the reproductive tract, make the males cryptorchid.
• Infectious causes or abortion/resorption in the Queen

  Feline leukaemia virus

  Feline herpes virus

  Feline panleucopenia virus

  Feline infectious peritonitis

  Chlamydia psittaci

  Toxoplasma gondii.
• Non-infectious causes or abortion/resorption in the Queen

  Abnormal uterine environment

  Fetal abnormalities

  Low progesterone
• Management of resorption/abortion

  Treatment of the dam at the time of abortion/ resorption.

  • Isolation from other dogs.
  • Systemic antimicrobial preparation (for secondary infection).
  • Ecbolic agents (oxytocin) to aid expulsion.
  • General/ specific nursing care - IVFT
• Dystocia - clinical history

  Has the dam given birth before - of so where there complications and what were these?

  What has recently been observed in this dam?

  Has there been recent vulval discharge.

  Have uterine/ abdominal contractions been noted and if so when?

  Have fetal membranes/ fluid been expulsed?

  Have foetuses been delivered?
• What are the methods for assessing possible dystocia cases?

  Clinical history (mating 58-72 days before onset of parturition).

  63 days from ovulation.

  Decline in plasma progesterone (1.5 days before onset parturition)

  Decline in rectal temperature (24 hours before onset parturition)

  Onset of uterine contractions (2 to 4 hours before onset parturition)

  Onset of abdominal contractions (30 to 120 minutes before onset parturition).
• What is the normal Foetal heart rate?

  170-230 bpm

  • Or at least four tomes maternal heart rate
  • Transient increases with foetal movement.
• What do the abnormal levels of foetal heart rate indicate?

  Foetal heart rate less than 150bpm:

  • Indicated stress (hypoxia)

  Foetal heart rate less than 130bpm

  • Poor survival if not delivered within 2-3 hours

  Foetal heart rates less than 100bpm

  • Immediate (medical or surgical) intervention to hasten delivery before demise of the pups.
• Treatment for dystocia

  Correction of foetal orientation

  • Retropulsion, correct position/ posture
  • Traction

  Oxytocin administration:

  • After correction of obstruction
  • Half life is short.

  Calcium administration