Equine Pregnancy Problems Flashcards
1
Q
What hormones are involved in pregnancy
A
- Progesterone
- Estrogens
- eCG
- Relaxin
2
Q
Where does progesterone come from during pregnancy? How do these sources maintain pregnancy?
A
-
Ovarian source is essential for maintenance of pregnancy until ~day 100
- >1 ng/ml indicates presence of luteal tissue
- ≥ 4 ng/ml consistent with pregnancy
- <4 ng/ml if pregnant supplementation for pregnancy maintenance
- Primary CL formed from the follicle that ovulated the oocyte
- Progesterone levels peak around day 20 then decline until approximately days 40-45
- Secondary follicles and CL
- Development of endometrial cups occurs approximately days 35-38
- Functional until approximately day 120
- Production of equine chorionic gonadotropin (pregnant mare serum gonadotropin)
- expresses both TSH and LH-like activities resulting in secondary CL
-
Feto-placental progestogen production begins ~ day 70-80
- Generally sufficient to maintain pregnancy after day 100
- Low measurable maternal progesterone during this time
- Maternal progesterone may drop <4 ng/ml after sloughing of endometrial cups
- Progesterone peak just before foaling
3
Q
What hormones are responsible for pregnancy and fetal viability?
A
- Progestogens
- Estrogen - Estrone Sulfate
4
Q
What do the different changes in progestogen levels mean?
A
- Progestogens
- Assays for progestogens produced by fetoplacental unit are not readily available
- Some commercial P4 assays will cross-react
- Rapid Decline (acute cases)
- frequently seen in acute conditions where fetal death has occurred or expulsion is imminent
- Precocious Rise (Chronic cases)
- associated with fetal stress or placental pathology
- Elevations for 2-3wks prior to day 310-320 are more likely to deliver live foals
- Linked to accelerated adrenal gland maturation thus increasing production of fetal progestins leading to increased peripheral progestins in circulation
5
Q
Where is estrogen sourced from during pregnancy? what do the levels mean?
A
- After day 55 - source form fetal-placental unit
- After 3rd month of pregnancy good marker of fetal viability
- Fetal death leads to rapid decline in estrogen levels within a few days
6
Q
What is placentitis?
A
- leading cause of:
- abortion
- premature birth
- still birth
- hypoxic or septicemic foals
- Infection of the placenta
- ascending infection of bacteria
- transcervical
- Diffuse
- hematogenous
- ascending infection of bacteria
7
Q
What is the clinical presentation of placentitis?
A
- Premature udder development
- Premature lactation
- +/- vaginal discharge
- Spontaneous abortion
- Birth of septic/hypoxic
8
Q
What causes Ascending placentitis?
A
- Associated with poor anatomical barriers
- Poor perineal confirmation
- Poor cervical function/tone
- Bacteria
- S. zooepidemicus
- E. coli
- K. pneumoniae
- P. aeruginosa
- Fungal
- Aspergillus sp.
9
Q
What is Ascending placentitis? what symptoms?
A
- Organisms originate form the vagina, skin, feces, or environment
- Ascends through the cervix to the cervical star
- Depleted area of villi
- Thickened
- Discolored
- Fibronecrotic exudate
10
Q
How can placentitis be diagnosed pre-partum?
A
- External clinical signs
- premature udder development
- premature lactation
- vaginal discharge
- Culture and sensitivity of vaginal discharge of from external cervical os
- Combined utero-placental thickness
- endocrine testing
- Blood progesterone
- estrogens
11
Q
How is combined utero-placental thickness measured?
A
- Performed at the caudal allantochorion
- Cranial of the cervical-placental junction
- landmark
- middle branch of the uterine artery along the ventral aspect of the uterine body
- Measure:
- caudal, ventral edge of the uterus between the middle branch of the uterine artery and the allantoic fluid
12
Q
How is fetal stress assessed using transabdominal US?
A
- Assess fetal well-being
- normal HR during late gestation ~80 bpm (60-110)
- Consistently low or high are associated with fetal stress
- Evaluate for areas of placental separation
- Echogenicity of fetal fluids
- Fetal activity
13
Q
What are the treatments for placentitis?
A
- Prolong gestation as long as possible: ≥ 320 days
- Chronic in-utero stress leads to accelerated fetal maturation
- Broad spectrum antibiotics
- Trimethoprim-sulfonamide 30 mg/kg PO BID
- Penicillin and gentamicin
- Anti-inflammatory
- Flunixin meglumine 1.1 mg/kg IV or PO for 7 days
- Promote uterine quiescence
- altrenogest 0.044 PO BID or 0.088 mg/kg PO SID
- Anti-endotoxic and rheologic
- pentoxifylline 8.4 mg/kg PO TID-QID
- Anti-oxidant
- Vitamin E
14
Q
What causes hematogenous placentitis?
A
- Leptospira interogans spp (multiple serovars)
- Nocardioform actinomycete
- Crossiella equi or Amycolatopis spp
15
Q
What happens in hematogenous placentitis caused by leptospira interrogans spp.?
A
- subspecies pomona - most abortions
- Mare is typically systemically ill
- Infects the fetus hematogenously
- results in abortion, stillbirth, premature live birth
- Dx: Placenta - spirochetes on silver stain
25
Q
What is Mare Reproductive Loss Syndrome?
A
- Pathogenesis: Unknown
- Ingestion of Eastern Tent Caterpillar
- Barbed setae on cuticle that may contain bacteria penetrate the intestine and distribute hematogenously throughout the mare
- Foals: early fetal loss, late fetal loss, pericarditis, pneumonia, umbilical cord inflammation, neurological disease, asphyxia
- Adults: placental separation (red bag), pericarditis and uveitis
28
Q
Why does Prepubic tenon rupture occur? what happens after?
A
- Occurs:
- late gestation
- predisposed mares - hydrops, twins, lack of muscle tone
- Post rupture:
- Present with abdominal pain and reluctance to walk
- Abdomen is dependent ventrolateral and has thick plaque of edema
- Udder loses support, blood vessels in the mammary gland can rupture resulting in blood in the milk
- Treatment:
- abdominal support
- induced assisted foaling
- C-section
- Poor Prognosis
- Mares should not carry future pregnancies
