section name header

Basics ⬇

Outline

BASICS

Definition!!navigator!!

  • Inflammation, lacerations, adhesions, and inability to dilate during estrus
  • Congenital abnormalities and neoplasia of the cervix uncommon

Pathophysiology!!navigator!!

  • The mare's cervix is a tubular structure 5.0–7.5 cm long and 3.5–4.0 cm in diameter, which protects the uterus from the external environment and contamination
  • The cervix is formed by an inner circular smooth muscle layer, rich in collagen elastic fibers, and an outer longitudinal smooth muscle layer connecting the vagina with the uterus
  • The cervix opens/relaxes depending on hormonal influence and the stage of estrus
  • Impaired normal cervical function and competency may lead to infertility, chronic uterine infections, and possible pregnancy loss

Systems Affected!!navigator!!

Reproductive

Genetics!!navigator!!

N/A

Incidence/Prevalence!!navigator!!

Lacerations are more common in old and/or pluriparous mares. Lack of cervical relaxation is more common in old maiden mares and mares with fibrosis due to extensive cervical manipulation.

Signalment!!navigator!!

  • Old (mean age 11–13 years), pluriparous mares (mean parity before surgery 6.2 years) after either normal parturition or dystocia. These mares are more predisposed to cervicitis caused by pneumovagina, urovagina, delayed uterine clearance, and endometritis
  • Young or old, maiden mares

Signs!!navigator!!

Historical Findings

  • Infertility
  • Poor uterine drainage
  • Chronic or recurrent endometritis
  • Pyometra
  • Pregnancy loss

Physical Examination Findings

  • Poor perineal conformation
  • Pneumovagina, urovagina, exudate coming through the cervix; cervical and vaginal mucosal irritation; cervical lacerations or mucosal roughness; adhesions between the cervix and vaginal fornix or in the cervical lumen
  • Manual examination of the cervix:
    • During diestrus—to evaluate cervical closure and tone, the presence and extent of lacerations or adhesions
    • During estrus—extent of cervical dilation, assess cervical patency, ability to relax, the presence of intraluminal adhesions
  • Ultrasonography of the uterus—presence of intrauterine fluid before or after breeding, quantity, and flocculence

Causes!!navigator!!

Infectious

  • Poor perineal conformation
  • Severe acute cervicitis after inoculation/infection with Taylorella equigenitalis (contagious equine metritis)
  • See also chapters Endometritis and Placentitis

Noninfectious

Cervical Trauma

Parturition, manipulation, and traction; extended fetal pressure against the cervical walls; and use of a fetotome can cause bruising of the cervix.

Two Types of Lacerations

  • Overstretching or partial-thickness laceration of the muscular layer with intact mucosa
  • Full-thickness laceration occurring during normal, prolonged parturition or dystocia, most frequently occurring in the vaginal portion of the cervix but may extend toward the uterus as far as, and including, the internal cervical osAdhesions
  • Sequela of cervical trauma during parturition or originating from the use of irritating solutions for uterine therapy, pyometra, and, rarely, chronic endometritis
  • Can obliterate the cervical lumen and prevent it from opening and closing properly

Cervicitis

  • Iatrogenic, e.g. chemical substances placed in the uterus
  • Secondary to trauma, e.g. parturition, dystocia, obstetric manipulation

Idiopathic

  • Maiden mares (young or old) with impaired cervical relaxation during estrus with no associated fibrosis or adhesions
  • Older mares that have undergone numerous embryo transfer flushes or cervical manipulation can develop a fibrotic cervix or adhesions preventing cervical relaxation
  • Maiden mares that conceive will dilate their cervix normally at parturition while a fibrotic cervix is at greater risk of tearing

Neoplasia

Very rare.

Developmental Abnormalities

Rare

Congenital Incompetency

Cervical aplasia, hypoplasia, and double cervix.

Risk Factors!!navigator!!

  • Pluriparous and old mares
  • Prolonged natural or assisted parturition
  • >2 or 3 cuts with the fetotome
  • Maiden mares
  • Aggressive uterine therapy
  • Concurrent acute and chronic endometritis
  • Pyometra

Diagnosis ⬆ ⬇

Outline

DIAGNOSIS

Differential Diagnosis!!navigator!!

Other causes of vaginal discharge:

  • Urovagina/uterus
  • Endometritis
  • Pyometra
  • Placentitis
  • Cystitis/urolithiasis

CBC/Biochemistry/Urinalysis!!navigator!!

N/A

Other Laboratory Tests!!navigator!!

N/A

Imaging!!navigator!!

Transrectal ultrasonography—fluid accumulation in the uterine lumen caused by a tight cervix, e.g. while still in estrus after breeding or adhesions. If cervix is incomplete owing to a laceration the accumulation of fluid may be due to inflammation and endometritis. Length and width of the cervix can be determined as well as defects of or within the cervix.

Other Diagnostic Procedures!!navigator!!

Cervical Examination

  • The cervix is examined by TRP, direct visualization with a speculum, and direct vaginal/digital palpation. The last is recommended over speculum examination
  • TRP—determines the size, tone, length, and degree of relaxation
  • Vaginoscopy—provides information regarding cervical and vaginal color, e.g. hyperemia; presence of edema, secretions, e.g. pus, urine; cysts, varicose veins, or adhesions between the cervical os and vagina
  • Digital palpation of the cervix is essential to evaluate lacerations or intraluminal adhesions. It is performed by placing the index finger into the cervical lumen and the thumb on the vaginal side of the cervix, then feeling carefully around its full perimeter for defects and throughout the lumen to the internal os
  • During the noncycling phase of the year, place mare on exogenous progesterone for 7 days to evaluate cervical tone, competency, and its ability to close
  • Only major defects can be detected immediately postpartum. Evaluate 6 days post ovulation after foal heat for maximal closure and competency. If the cervix has a questionable defect or closure an additional 7 days of exogenous progesterone can aid in diagnosis

Pathologic Findings!!navigator!!

N/A

Treatment ⬆ ⬇

Outline

TREATMENT

Appropriate Health Care!!navigator!!

  • Treatment of choice for cervical lacerations depends on the severity (thickness) and extent (length) of the lesion
  • Mucosal and submucosal lacerations (up to two-thirds thickness of the wall) can be treated daily with antimicrobial/steroidal anti-inflammatory ointment to avoid cervical adhesions while healing
  • Begin treatment of cervical lacerations immediately postpartum to prevent adhesions and infection
  • Cervical lacerations of the external os or up to one-third of the length of the cervix may be managed using exogenous progesterone supplementation during diestrus (starting day 6 post ovulation) as long as persistent endometritis does not exist, and pregnancy can be achieved
  • Cervical defects more than one-third of the length should be surgically corrected. Healing occurs with fibrous tissue, which lacks the ability to relax or soften as occurs with normal cervical smooth muscle
  • Potential postsurgical problems—incomplete cervical dilation/relaxation, retention of intraluminal fluid, adhesions, pyometra, recurrent cervical lacerations during parturition that require repair

Treatment for adhesions

  • Recently formed adhesions are debrided daily (manual), and antibiotic/steroid ointment is applied BID
  • Cervical adhesions may be bypassed manually by artificial insemination or reduced surgically, recognizing that lack of cervical relaxation affects uterine clearance

Treatment for lack of cervical dilation

  • Postbreeding treatment for delayed uterine clearance.
  • Manual dilation of the cervix
  • Prostaglandin E1 (misoprostol) placed on/in the cervix
  • N-butylscopolammonium bromide (hyoscine butylbromide; Buscopan) cream on/in the cervix. Topical creams relax the muscular cervix better than a fibrotic cervix
  • A cervical wedge resection can be performed on the old fibrotic cervix that does not dilate. However, since closure is then incomplete, assisted reproductive techniques, e.g. embryo transfer, are necessary to establish pregnancy

Nursing Care!!navigator!!

  • When using antiseptics or nonbuffered antibiotics, check for signs of acute mucosal irritation before administering subsequent treatments
  • Following cervical surgical repair—palpation of the cervical canal is necessary to prevent adhesion formation

Activity!!navigator!!

N/A

Diet!!navigator!!

N/A

Client Education!!navigator!!

  • Routine postpartum evaluation of the reproductive tract of the mare, especially when there is a history of assisted, prolonged manipulation or unassisted, traumatic parturition
  • Early identification and treatment of traumatic injuries avoids loss of time during the breeding season; decreases the risk for infertility
  • Lack of cervical relaxation necessitates treatment for poor uterine clearance

Surgical Considerations!!navigator!!

  • Cervical repair may be warranted for small cervical lacerations if coupled with a history of infertility and chronic endometritis
  • Surgery can be performed standing under epidural anesthesia; if the cervical lesion is extensive or difficult to visualize (usually ventral lesions) general anesthesia and hoisting the pelvic limbs to achieve a Trendelenburg position may be necessary:
  • Cervical adhesions should be identified by palpation per vagina and reduced by sharp or blunt dissection depending on the extent of external versus internal cervical involvement
    • Excess scar tissue may be trimmed
    • Before and after surgery—mares are usually administered broad-spectrum antibiotics and anti-inflammatories
  • With a successful surgical repair, prognosis is fair to good for delivering a term foal
  • Anatomic defects resulting in cervicitis, such as pneumovagina and urovagina, can be surgically corrected by a Caslick vulvoplasty or a Pouret or Gadd procedure
  • Perform endometrial biopsy before surgery to evaluate the endometrium (biopsy category). Unnecessary repair and expense can be avoided if it is found that surgery cannot improve the mare's ability to carry a fetus to term

Medications ⬆ ⬇

Outline

MEDICATIONS

Drug(s) of Choice!!navigator!!

  • Progestin supplementation (altrenogest)
    • Double dose (0.088 mg/kg PO daily) during surgery
  • Systemic and oral antibiotics
    • See chapter Endometritis
  • NSAIDs
  • Prostaglandin E1 for cervical relaxation—misoprostol 2000 μg/3 mL tube intracervically 4 h before breeding. Cervix will be dilated for 8 h
  • Less effective in older mares with previous cervical trauma
  • Frequent application produces irritation
  • N-butylscopolammonium bromide (Buscopan) cream aids in normal cervical relaxation more than with a fibrotic cervix
  • Local therapy
    • Anti-inflammatory, antibiotic, and antifungal cream (Panalog or Animax). Frequency of application is based on severity of lesion or adhesions

Contraindications!!navigator!!

See chapter Endometritis.

Precautions!!navigator!!

  • Certain antiseptics and nonbuffered antibiotics should be used with caution to treat infections of the vagina and uterus since some can cause inflammation and adhesions
  • Minimize forced extraction during dystocia, use ample lubrication, and consider cesarean section in cases with intractable cervical induration, poor dilation of the birth canal, as well as with large, deformed, or contracted foals

Follow-up ⬆ ⬇

Outline

FOLLOW-UP

Patient Monitoring!!navigator!!

  • Palpation of the cervix and application of sterile lube, an antiadhesion cream, or steroid/antibiotic cream—commence 5–7 days post surgery, continue every 3–4 days for approximately 21 days so that adhesions and stricture of the cervical canal may be prevented
  • Sexual rest for 4–6 weeks
  • If live cover is necessary, i.e. Thoroughbreds, the use of a stallion roll is advised to limit full intromission during cover

Prevention/Avoidance!!navigator!!

  • Unnecessary manipulation during parturition
  • Use of irritants
  • Check for normalcy of anatomic barriers that protect the genital tract (perineum, vulva, vestibulovaginal sphincter, and cervix); repair any defects

Possible Complications!!navigator!!

  • The scar/site of repair lacks the elasticity of normal cervical tissue. A high percentage will tear again at the next foaling and require annual surgical repair after foaling
  • Cervical repair usually prevents complete relaxation during estrus; treatment for delayed or poor uterine clearance may be necessary
  • The decision to perform subsequent surgeries is based on the degree of cervical damage after the most recent foaling, assessment of surgical cost, and breeding/treatment expenses versus the potential value of an additional foal
  • Lack of cervical dilation or continued/reformed adhesions lead to poor uterine clearance, potentially producing chronic retention of intraluminal fluid, chronic endometritis, and pyometra

Expected Course and Prognosis!!navigator!!

  • Fair to good for maintenance of pregnancy after successful repair of cervical lacerations
  • Guarded prognosis if repair was extensive or unsuccessful

Miscellaneous ⬆ ⬇

Outline

MISCELLANEOUS

Associated Conditions!!navigator!!

N/A

Age-Related Factors!!navigator!!

Most common in old, pluriparous mares and young or old maiden mares.

Zoonotic Potential!!navigator!!

N/A

Pregnancy/Fertility/Breeding!!navigator!!

See Expected Course and Prognosis.

Abbreviations!!navigator!!

  • NSAID = non-steroidal anti-inflammatory drug
  • TRP = transrectal palpation

Suggested Reading ⬆ ⬇

Blanchard TL, Varner D, Schumacher J. Surgery of the mare reproductive tract. In: Manual of Equine Reproduction. St. Louis, MO: Mosby, 1998:165–167.

Makloski-Cohorn CL. Post-operative fertility in mares with cervical defects. Masters thesis. Oklahoma State University, 2009.

O'Leary JM, Rodgerson DH. Foaling rates after surgical repair of ventral cervical lacerations using a Trendelenburg position in 18 anesthetized mares. Vet Surg 2013;42:716–720.

Sertich PL. Cervical problems in the mare. In: McKinnon AO, Voss JL, eds. Equine Reproduction. Philadelphia, PA: Lea & Febiger, 1993:404–407.

Author(s) ⬆

Author: Karen Wolfsdorf

Consulting Editor: Carla L. Carleton

Acknowledgment: The author and editor acknowledge the prior contribution of Maria E. Cadario.