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Pregnancy Termination 819

Pregnancy Termination Bonus Material Client Education
Online
Sheet
VetBooks.ir Diseases and Disorders
BASIC INFORMATION
• Pyometra
• Mucometra/hydrometra at 7-15 days. Treatment efficacy is highest
when treated up to 10 days after day 35 of
Definition gestation. Treatment failure has been reported
Elective nonsurgical abortion of a litter before Initial Database in bitches treated between 30 and 35 days’
55 days’ gestation, with gestation based on days The diagnosis of pregnancy can be made with gestation. Concurrent treatment with PGF 2a
from the luteinizing hormone (LH) surge (term abdominal ultrasound, serum relaxin assay, or does not improve efficacy.
= 65 ± 1 days) abdominal radiographs. Advantages, drawbacks, • Aglepristone (in bitches and queens) 10 mg/
and expected results of each are discussed on kg SQ, two doses 24 hours apart. Aglepris-
Synonyms p. 816. tone is a progesterone receptor antagonist and
Abortion (elective), mismating/misalliance has few side effects. It is not manufactured
options TREATMENT in the United States. It may be administered
Epidemiology Treatment Overview during mid-pregnancy and has been suc-
cessful in terminating pregnancies between
SPECIES, AGE, SEX • Reduce serum progesterone concentrations 23-42 days after breeding. Side effects include
Postpubertal intact bitches and queens to < 2 ng/mL by lysis of the CLs (luteolysis) localized swelling at the injection site.
for a period of >48 hours.
RISK FACTORS • Perform a complete evacuation of the uterus. Chronic Treatment
Intact cycling females • The owner and clinician should discuss the If pregnancy termination does not occur after an
advantages and drawbacks of medical versus initial treatment, and pregnancy termination is
ASSOCIATED DISORDERS surgical (ovariohysterectomy) pregnancy still desired, the protocol should be continued
Depending on the method of pregnancy termi- termination to develop an appropriate or a different treatment regimen should be used.
nation and on timing, pyometra, pseudocyesis, treatment plan.
or delivery of premature viable offspring may Behavior/Exercise
occur. Acute General Treatment Depending on the pregnancy termination
Depending on the protocol, luteolysis can be method used, pseudocyesis (inappropriate lacta-
Clinical Presentation induced before or after a pregnancy diagnosis tion) may develop. If this occurs, dams should
DISEASE FORMS/SUBTYPES has been made. not be allowed to lick the mammary glands
Stages when pregnancy termination may be • Prostaglandin F 2alpha (PGF 2a ) therapy can because it may stimulate further lactation.
performed: be initiated as soon as day 5 of diestrus, as
• Before pregnancy diagnosis (<20 days past determined by vaginal cytologic exam, and Possible Complications
the onset of the LH surge) as late as day 45. • Side effects secondary to pregnancy termination
• Before fetal ossification (20-44 days past the ○ Canine: dinoprost 0.1-0.25 mg/kg SQ q include anorexia, vaginal discharge, discomfort,
onset of the LH surge) 8-12h to effect, usually 3-9 days of therapy depression, and shortened interestrous interval
• After fetal ossification (>44 days past the is needed, or cloprostenol 1-2.5 mcg/kg at the first estrus after treatment.
onset of the LH surge) q 24-48h for 4-5 injections is needed. • Side effects of PGF 2a (occur 30-40 minutes
○ Feline: dinoprost 0.25-0.5 mg/kg SQ q after injection; decrease with subsequent
HISTORY, CHIEF COMPLAINT 8-12h to effect; usually 3-9 days of therapy injections) include salivation, panting, vomit-
Female bred to an unintended male and/or at is needed. ing, defecation/diarrhea, and vocalization in
an unintended time • Combination (preferred method) of PGF 2a queens.
with a prolactin inhibitor (may cause severe
PHYSICAL EXAM FINDINGS vomiting in cats) Recommended Monitoring
• Typically healthy female ○ PGF 2a SQ q 8h (dosage as listed above); Ultrasonography and serum progesterone
• Abdominal palpation of focal, discrete uterine PGF 2a may be needed for an additional concentrations to verify completion of abortion
enlargements during the fourth week of 1-2 days after the last treatment with a and uterine evacuation
gestation. Accuracy depends on the expertise prolactin inhibitor for complete uterine
of the examiner and the stage of pregnancy. evacuation. PROGNOSIS & OUTCOME
○ Prolactin inhibitor: bromocriptine 10 mcg/
Etiology and Pathophysiology kg (0.01 mg/kg) or cabergoline 5 mcg/kg Good prognosis for future fertility
• Ovarian progesterone production from the (0.005 mg/kg) PO q 8h. Usually, 3-4 days
corpora lutea (CLs) is required for the entire of therapy are needed. Protocols using PEARLS & CONSIDERATIONS
duration of a canine or feline pregnancy. prolactin inhibitors are initiated during
• Pregnancy in the bitch and queen can be the middle third of pregnancy (20-44 Comments
terminated by administration of drugs that days from the onset of the LH surge), • Because >50% of bitches are not pregnant
prematurely lyse CLs. when the clinician is able to verify the after a misalliance situation, waiting until
diagnosis of pregnancy by palpation or the pregnancy is positively diagnosed to
DIAGNOSIS ultrasonography. begin a protocol to terminate a pregnancy
• Prolactin inhibitor in queens: cabergoline is recommended.
Diagnostic Overview 25-50 mcg/CAT PO q 24h for 3-5 days • Administration of estrogen during estrus has
Pregnancy diagnosis (p. 816) • Dexamethasone (in bitches) 0.1-0.2 mg/ been reported to be effective, but it is not
kg PO q 8-12h at decreasing dose for considered standard of care for pregnancy
Differential Diagnosis 5-10 days or 5 mg IM q 12h for 10 days termination.
For pregnancy: (large dog). Fetal death occurs 5-13 days • The combination protocols using PGF 2a and
• Pseudopregnancy after treatment, and fetal expulsion starts prolactin inhibitors achieve success more

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