Eutocia/Dystocia Flashcards
What changes occur in the mother prepartum ?
Udder edema and milk production 1-2weeks prior (waxing)
Relaxation of pelvic ligaments > raised tail head (sacrosciatic and sacrotuberous ligaments)
Elongation and softening of the vulva
Dilation and opening of the cervix just prior to parturition
Melting of the cervical plug > appears at the vulva
What are the mechanisms leading to parturition?
Maturation of fetal hypothalamic-hypophyseal-adrenal axis
Increased sensitivity of the fetal adrenal glands to ACTH
Increased fetal corticoids from adrenal cortex
Activation/conversion of placental enzyme systems
—decreasing progestagens
—increasing estrogen precursors and estrogens
Relaxin and prolactin
Uterine — up regulation of oxytocin receptors and release of prostaglandin F2a
What is stage 1 of eutocia?
Initiation of myometrial contractions (initiated by fetus)
Usual duration 1-6hours
Clinical signs of stage 1 of eutocia
Restlessness Anorexia Signs of abdominal discomfort Increased pulse and respiration Nesting/isolation form others Shifting weight Arched back elevated tail
Dilation of cervix
Where do contractions begin in a monotocous or polytocous species?
Monotocous — apex of the pregnant horn
Polytocous — cranial to most caudal fetus
“Breaking water” is a rupture of the _______________ membrane
Chorioallantoic
What occurs in stage 2 of parturition?
Delivery of fetus
Begins with rupture of chorioallantois
30-60mintues
Active straining/abdominal press
Rupture of the amnion
Ferguson’s reflex
Dam lies in sternal recumbency then lateral for delivery
What is Ferguson’s reflex?
Wedging of fetus into cervical canal stimulates oxytocin release, which stimulates more uterine contractions
What is stage 3 of parturition ?
Expulsion of fetal membranes
What 3 P’s are used to describe the position of the fetus at parturition?
Presentation — relationship of the spinal axis of the fetus to that of the dam and the portion of the fetus that is entering the birth canal (longitudinal/transverse)
Position — anatomic relationship of the dorsum of the fetus relative to maternal pelvis (dorsal-sacral/dorsal-pubic/dorsal-ilial)
Posture — anatomic relationship of the fetal extremities to its own body (flexed/extended/retained)
What is dystocia?
Abnormal or abnormally difficult birth
More common amoung primiparous than multiparous (cattle greatest risk, cats lowest risk)
What are maternal causes of dystocia?
Primary uterine inertia — never progress to stage two, weak abdominal contractions, cervix usually dilated on exam
Secondary uterine inertia — exhaustion of myometrium after prolonged attempts to deliver fetus
Abnormalities of birth canal
— inadequate size of pelvis, pelvic deformities, incomplete cervical dilation, neoplasms, persistant Müllerian ducts
What are fetal causes of dystocia?
Abnormal presentation, position, and posture
Fetal monsters
Fetal oversize
What is a rare congenital anomaly where there is complete/partial agenesis of lumbar, sacral, or coccygeal vertebrae? Usually results in arthrogryposis of the hindlimbs and malformation of the musculature.
Peresomus elumbus
What do you call the congenital abnormality where there is failure of the body wall to close, resulting in an “inside-out” calf with external abdominal organs?
Shistosomus reflexus
What is usually the cause of fetopelvic dysporoportion?
Management related
Eg.
insufficient nutrition —> insufficient maternal growth
Excessive nutrition during later gestation —> rapid fetal growth
What traumatic conditions can lead to dystocia?
Herniation or rupture of the prepubic tendon may disallow abdominal press
Torsion of the uterus creates mechanical stress of tubular tract
Fractures of the pelvis - if not healed in apposition, may reduce size of bony pelvic canal
What type of history do you want to get in a dystocia?
Length of problem
Who has attempted deliver
A heifer presents for a dystocia. You are going to do a vaginal exam to look for???
Tears Fibrosis Dilatation Elasticity Lubrication
To do a vaginal exam, how are you going to prepare the area?
Wash vulva and perineum with warm water and mild antiseptic solution (eg dilute iodine)
When examining the fetus, how can you determine if it is alive?
Positive response to pedal, palpebral, eyeball,, mouth and anal pressure by movement reflex
Excessive movement of extremities or tongue may indicate hypoxia
What do you call the process by which the fetus is restored to deliverable fashion?
Mutation
What do you call pushing the fetus out of the maternal pelvisinto the uterine cavity to enable correction of an abnormality?
Repulsion
What do you call turning the fetus on its longitudinal axis?
Rotation
