pregnancy loss and parturition
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Pregnancy Loss and Parturition. John Parrish. Distribution of Prenatal Losses. Fertilization 100% Under optimal conditions 2/3 loss during embryonic development Imprinting Compaction Blastocyst hatching and formation Failure to prevent CL regression Maternal recognition of pregnancy. - PowerPoint PPT PresentationTRANSCRIPT
Updated:04/22/23
Pregnancy Loss and
Parturition
John Parrish
Updated:04/22/23
Distribution of Prenatal Losses
• Fertilization 100%»Under optimal conditions
• 2/3 loss during embryonic development» Imprinting
»Compaction
»Blastocyst hatching and formation
»Failure to prevent CL regression • Maternal recognition of pregnancy
Updated:04/22/23
Distribution of Prenatal Losses (cont.)
• 1/3 loss during fetal stage»Crowding
»Placental insufficiencies
»Not the fetus directly
Updated:04/22/23
Embryonic and Fetal Loss in Cattle
0102030405060708090
100
0 1 2 3 5 Calving
Pregnancy Loss
Interval From Breeding (months)
Per
cen
tag
e
Updated:04/22/23
Embryonic and Fetal Loss in Pigs
10
12
14
16
18
20
0 25 400
20
40
60
80
100Number Survival (%)
Stage of Gestation (days)
Nu
mb
er
of
CL
s, E
mb
ryo
s o
r F
etu
se
s P
res
ent
% S
urv
iva
l
Updated:04/22/23
Increased Prenatal Loss
• Nutritional Stress»Energy shortages
»Mineral imbalances
»Vitamin deficiencies
• Disease of the reproductive tract
• Endocrine imbalances
• Aging of gametes prior to fertilization
Updated:04/22/23
Effect of Oocyte Age on Fertilization and Embryo Viability
0
20
40
60
80
100
0 4 8 12 16 204
6
8
10
12
% O
ocy
tes
Fer
tili
zed
No
rmal
ly%
Oo
cyte
s F
erti
lize
d N
orm
ally
Via
ble
Em
bry
os
at 2
5 D
ays
of
Pre
gn
ancy
Via
ble
Em
bry
os
at 2
5 D
ays
of
Pre
gn
ancy
Age of Oocyte at Fertilization
Updated:04/22/23
Parturition
Updated:04/22/23
Mechanism For Parturition
Skunk Cabbage Prolonged gestation in Sheep hypoplasia of Anterior Pituitary
Gene Defect Autosomal recessive in Holstein cattle Large calves, 1-2 months beyond due date hypoplasia of Anterior Pituitary
Updated:04/22/23
Fetal Adrenal Changes with Age
Fetal Age
Ad
ren
al G
lan
d W
eig
ht
ParturitionParturition
Change in Adrenal Size is a Response to Stress!!
• Lack of space
• Lack of gas exchange
• Lack of nutrients
Change in Adrenal Size is a Response to Stress!!
• Lack of space
• Lack of gas exchange
• Lack of nutrients
Updated:04/22/23
Hormonal Changes Associated with Parturition
Updated:04/22/23
ParturitionFetal Nutritional
DemandsFetal Nutritional
Demands
PlacentalInsufficiency
PlacentalInsufficiency
HypothalamusAnteriorPituitary
Adrenal Cortex
CRHCRH ACTHACTH
Fetal Corticosteroids(Cortisol)
Fetal Corticosteroids(Cortisol)
Updated:04/22/23
ParturitionFetal Nutritional
DemandsFetal Nutritional
Demands
PlacentalInsufficiency
PlacentalInsufficiency
HypothalamusAnteriorPituitary
Adrenal Cortex
CRHCRH ACTHACTH
Fetal Corticosteroids(Cortisol)
Fetal Corticosteroids(Cortisol)
Lung(surfactant)
Lung(surfactant)
Liver(glycogen)
Liver(glycogen)
Thyroid(metabolism)
Thyroid(metabolism)
ProgesteroneProgesterone EstrogenEstrogen PGF2PGF2
PlacentomePlacentome
Updated:04/22/23
ParturitionFetal Nutritional
DemandsFetal Nutritional
Demands
PlacentalInsufficiency
PlacentalInsufficiency
HypothalamusAnteriorPituitary
Adrenal Cortex
CRHCRH ACTHACTH
Fetal Corticosteroids(Cortisol)
Fetal Corticosteroids(Cortisol)
Lung(surfactant)
Lung(surfactant)
Liver(glycogen)
Liver(glycogen)
Thyroid(metabolism)
Thyroid(metabolism)
ProgesteroneProgesterone EstrogenEstrogen PGF2PGF2
UterineContractions
UterineContractions
PGF2
Relaxin
Oxytocin
Uterine Endometrium» Oxytocin receptors
Uterine Myometrium» Gap junctions
Ovary(CL)
Cow,SowTriggers
CLRegression
PlacentomePlacentome
CervicalRipeningCervicalRipening
Updated:04/22/23
Final Role of OxytocinSensory Neurons in CervixSensory Neurons in Cervix
Oxytocin fromPosterior Pituitary
Oxytocin fromPosterior Pituitary
MyometrialContractionsMyometrial
Contractions
Updated:04/22/23
Orientation of Fetus
• Fetus must reorient prior to parturition» Initially on back
»Reorient so feet and head will exit first
»Breech• Rear of fetus comes first
• Orientation not important in pig
• Abnormal orientation results in dystocia
Updated:04/22/23
Fetal Orientation
Updated:04/22/23
Fetal Orientation
Updated:04/22/23
Stages of Labor
• Preparative (2 to 12 hours)»Myometrial contractions
»Uterine pressure
»Abdominal discomfort
»Cervical dilation
Updated:04/22/23
Stages of Labor (cont.)
• Expulsion of fetus (30 to 180 min)»Strong uterine contractions
»Rupture of the allantochorion
»Appearance of the amnion
»Maternal recumbence and straining
»Not only uterine but abdominal contractions as well
»Rupture of the amnion and delivery
Updated:04/22/23
Stages of Labor (cont.)
• Expulsion of the placenta (1 to 12 hours)»Uterine contractions
»Chorionic villi loosen
»Expulsion of the placenta
»Delayed in ruminants due to presence of cotelydons separating independently
»Suckling induces oxytocin release which triggers further uterine contractions
Updated:04/22/23
Dystocia
• Difficult birth
• Excessive fetal size (90% for cattle)
• Abnormal presentations (5% for cattle)
• Multiple births (twins)»Twins presented at the same time
»One is usually blocking the other
»Uterus becomes fatigued
Updated:04/22/23
Updated:04/22/23
Updated:04/22/23
Updated:04/22/23
Dystocia
Updated:04/22/23
Perinatal Fetal Changes
• Cardiovascular»Ductus arteriosis
»Foramen ovale
»Ductus venosus
Updated:04/22/23
Placenta
Liver
Left Atrium Lungs Right Atrium
ForamenOvale
ForamenOvale
DuctusVenosusDuctus
Venosus
DuctusArteriosus
DuctusArteriosusAorta
Umbilical Arteries
Umbilical Vein
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
Fetal CirculatorySystem
Fetal CirculatorySystem
Updated:04/22/23
Liver
Left Atrium Lungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
DuctusVenosusDuctus
Venosus
TransitionalCirculatory
System
TransitionalCirculatory
System
Updated:04/22/23
Liver
Left Atrium Lungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
TransitionalCirculatory
System
TransitionalCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Liver
Left Atrium Lungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
TransitionalCirculatory
System
TransitionalCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Liver
Left Atrium Lungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
TransitionalCirculatory
System
TransitionalCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Liver
Left Atrium LungsLungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
TransitionalCirculatory
System
TransitionalCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Liver
Left Atrium LungsLungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
TransitionalCirculatory
System
TransitionalCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Liver
Left Atrium LungsLungs Right Atrium
ForamenOvale
ForamenOvale
DuctusArteriosus
DuctusArteriosusAorta
Portal VeinPortal Vein
Vena CavaVena Cava
Headand Heart Tissues
AdultCirculatory
System
AdultCirculatory
System
DuctusVenosusDuctus
Venosus
Updated:04/22/23
Perinatal Fetal Changes• Cardiovascular
»Ductus arteriosis»Foramen ovale»Ductus venosus
• Thermoregulatory»Must regulate own temperature» Increase metabolism (thyroid activity)»Brown fat - metabolism of produces heat
• Energy metabolism»Until suckling, relies on own stores of
glycogen
Updated:04/22/23
Perinatal Fetal Changes (cont.)
• Immune status»Has no antibodies to protect
»Gets passive immunity from mother• Gut permeable to antibodies in colostrum• Only first 1 - 2 days• In rabbit, rat, man get some antibodies absorbed
through placenta
Updated:04/22/23
ParturitionParturition
ConceptionConception
Postpartum
Postpartum
Involution(2 - 3 weeks)Involution
(2 - 3 weeks)
UterusUterus
MyometriumMyometrium
Shrinkage and
atrophy
Shrinkage and
atrophy
EndometriumEndometrium
RepairRepair
LumenLumen
Elimination of bacteriaElimination of bacteria
HypothalamusHypothalamus
Anterior PituitaryAnterior Pituitary
OvariesOvaries
SteroidsSteroids FolliclesFollicles
Estrous Cycles(4 to 10 weeks)Estrous Cycles(4 to 10 weeks)
Updated:04/22/23
Return to Estrus
• Fertility increases with # of estrous cycles»First = 35% pregnancy rate
»Second = 50%
»Third = 73%
»Fourth = 72%
• Lactational anestrus or Lactational amenorhea
Updated:04/22/23
Return to Estrus (cont.)
• Special postpartum estrus»Mare - foal heat, 6 - 13 days postpartum
• Fertility depends on body condition
»Sow• Anovulatory estrus 3 - 5 days post-farrowing• Weaning induces estrus 3 - 5 days latter
Updated:04/22/23
Retained Placenta
• Definition» If not expelled within 24 hr it may be retained
for 5 - 6 days
• Most common in cattle (5 - 15 %)»Not seen in sows or ewes
»Sometimes seen in mares (retained = > 4 hrs)
Updated:04/22/23
Equine Retained Placenta
Updated:04/22/23
Retained Placenta (cont.)
• Cause»Normally get lack of blood flow to chorionic villi
and this causes them to regress
»High incidence in premature or early delivery
»High milk producers
»Twins
»Dystocia
» Induction of parturition
»Nutritional deficiencies• Vitamin A• Selenium
Updated:04/22/23
Retained Placenta (cont.)
• Treatment»Manual removal not recommended
»Daily antibiotics
»Large single antibiotic bolus
»Oxytocin or PGF
• Major concerns in humans and mares»Can cause death of mother from septicemia
Updated:04/22/23
Induction of Parturition
• Dexamethazone»Potent synthetic cortisol
»Works in all species
»Takes 2 to 3 days
• PGF2
»Swine, cattle and sheep
• Oxytocin»Human, horse
Review Remaining Slides for Species Specific Procedures!
Updated:04/22/23
Cow - Do not induce before last 7-14 Days of gestation
Method: Dexamethasone - parturition in 48 hours, 20-50 mg/IM
-High incidence of retained placentas and lower postpartum fertility (severity increases the earlier induced).
Azium (trade name) combined with 25 mg Lutalyse induces within 35+2 hours. Requires a live fetus to work and does not work on a mummified fetus
- Retained placenta is not problem if treated properly- Giving estrogen before induction of parturition incidence
Prostaglandins used in cases of a mummified fetus and are also effective in inducing abortion the first 4-5 months
Updated:04/22/23
Sheep - Best within a few days of parturition
Dexamethasone (8-20 mg) Parturition in 24-72 hours
Retained placenta not a problem
Can use Lutalyse to abort before Day 50 of gestation
Updated:04/22/23
Sow - Do after day 111 of gestation
PGF2 (Lutalyse 10 mg/IM) parturition in 29-48 hours.
Note that this is less than 3 Days from normal parturition
Close synchrony - Lutalyse at 8 AM followed by oxytocin 40 IU 24 hours later. Sows farrow between 8 AM and 5 PM (32 hours from start)
Piglets should be born within 1 to 8 (average 1-4) hours with15 minute intervals between piglets - May give oxytocin in last few piglets to decrease stillborn numbers in large litters or after extended delivery interval
Its is important to give PGF2 no earlier than Day 111. If given on Day 110 will cause stillborn piglets ( too immature to survive)
Updated:04/22/23
Mare - Do after day 320 of gestation Oxytocin (20-60 I.U.) close to term !!!
Takes less than 1 hour!Placenta expelled in < 1 hour
Make sure of the following before inducing foaling:
1. Udder is enlarged with presence of colostrum2. There is relaxation of the perineal region3. Cervical relaxation (can insert 1 to 2 fingers)
Usually induce for only two reasons: 1. Demonstration 2. Prolonged gestationIn normal pregnancy, mare can control time of day for foalingthrough her release of oxytocin. Inject oxytocin give no choiceof time.