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51 Cards in this Set
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- Back
Placenta |
The nutrient, gas exchange and waste removal organ of the fetus 6 to 8 inches in diameter Occupies 1/3 of intrauterine surface |
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Placenta |
Moms arterial blood O2, diffuses into umbilical vein Fetal blood picks up O2 Blood goes to through fetal circulation Fetal blood, high in CO2, returns back to the placenta via umbilical arteries CO2 diffuses into moms venous system and it is exhaled |
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Closer look at placenta |
The embryo implants into the uterus by finger like projections (chorionic villi) :These contain fetal vessels
As these continus to grow, the endometrium erodes, creating pockets (intervillous spaces) :These contain maternal blood
Cotyledon: grouping of 15 to 28 villi and intervillous spaces |
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Closer look at placenta |
Gas exchange takes place between fetal and maternal blood No contact between either blood source
Placenta to attack and build the upper 1/3 of the baby cavity, it stays away from the cervical opeing, so birth is not obstructed in any way. |
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Umbilical cord |
lifeline between fetus and mother Mean length 55 cm (22 inches) 3 vessels surrounded by whartons jelly :2 umbilical arteries/ 1 umbilical cord
AMNION: sack that surrounds the fetus and amniotic fluid |
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Amniotic fluid |
1t 40 weeks, 1 liter of fluid produced at 7 days Made of maternal and amniotic membrane fluid gIt is always being replenished and reabsorbed 24 to 26 weeks the fetal skin is permeable |
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Amniotic fluid |
Skin starts to harden after 26 weeks, so skin is impermeable to the fluid (keratinization)
Absorption is now done by fetal swalling (500 ml/day) and
Fluid in the amniotic sack is replenished by fetal urination and lung fluids (500 ml/day)
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Purpose of amniotic fluid |
Allows for fetal movement
Protects from shock or maternal movement
Thermoregulation
Helps metabolism by giving fluids to fetus |
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Polyhydramnios |
Abnormally high amounts of fluid :Greater than 2000 ml
Indicates a "swallowing problem of fetus :May also indicate abnormalities such as ::anencephaly ::Esophageal atresia ::TE fistula
Complication from this :PROM (premature rupture of membrane) :Lead to prolapse of cord :A premature delivery |
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Oligohydraminos |
Decreased amount of amniotic fluid less than 500 ml Caused by: :Urinary tract defect :Post term preganacy
Coplications :adhesion of body parts :compression of the umbilical cord leading to asphyxia :lung hypoplasia (failure of lung to deelop_ :limb deformaties :Potters syndrome (worse case scenario, this is always fatal)
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Fetal blood |
Higher affinity for oxygen due to higher hemoglobin content Lower levels of 2,3 DPG so the OXYGEN DISSOCIATION CURVE SHIFTS TO THE LEFT P50= 7.8 mmHg lower than the adult P50 of 27 mmHg Highest PaO2 is in the umbilical vein (29 mmHG) SaO2= 80% |
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Chemoreceptors |
Not present (or non functional) in fetus due to immaturity of carotid sinus
Located in carotid arteries and aorta
Sensitive to PaO2, PaCO2, pH
Regulation of ventilation and the baby's first breath
Cental chemo receptors are located in the brain steam, they are the primary chemoreceptors (depedant on CO2)
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Fetal to neonatal circulation |
Foramen ovale closes Ductus arteriosus closes Ductus venosus closed Decreased PVR for circulation to the lung |
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Decreased PVR/ lung circulation |
umbilical cord clamped Less blood returns to the right side of heart, so pressures decrease Left heart pressures increase because it is no longer pumping blood back to the low resistant placenta, it is now pumping to the systemic system
Lung fluid expelled, relieving pressure on the pulmonary vessels |
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Decrease LVR/ lung circulation |
Pulmonary vessels can now expand, hold more blood, decreasing PVR
Breathing starts and PAO2 increases causing vasodilation
With better pulmonary perfusion more blood is circulated to left atrium so left heart/system pressures increase
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Ductus venosus closes |
Remains open but not blood flow, function stops right away
Automatically closes within 3 to 7 days :functional closure happens when cord is cut
Due to lack of blood flow |
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Foramen ovale closes |
Closes via a flap valve when left pressures exceed right heart pressures
Happens immdiately
If right heart pressures exceed left, the foramen ovale can reopen allowing for shunting
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Ductus arteriosus closes |
Constricts and closes due to an increase in O2 tension
Decreased PVR allows right ventricle to pump blood easier into the lung and onto left heart, so there is less blood flow through the ductus arteriosus
DA DOES NOT CLOSE IMMEDIATELY
can take 24 hours to functionally close and up to 3 weeks to to structurally close |
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ductus arteriosus closes (most problems, and most connection with |
first hours: remains open but blood flow will be from the left to right because pressures are higher in left than right
Several hours later: constrictus due to higher PaO2
Functional closure 12 to 18 hours after birth
Total closed by 3 weeks
PROSTAGLANDINS keeps DA open in utero but are prohibited by high PaO2, causing constriction
INDOMETHICIN: GIven to hypoxic premature infants following delivery to help close DA (CLOSES DA)
Depending on CHD, need to keep open or to close |
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Factors responsible for 1st breath |
TRANSIENT FETAL ASPHYXIA: fetal circulation is cut off. Hypoxia and hypercapnia arise. Chemoreceptors stimulated
THORAX COMPRESSED ON delivery, lung fluid removed, then reexpands for air entry
ENVIRONMENTAL STIMULATION
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First breath |
-60 to -100 cmH20, but decrease on subsequent breaths
VT= 40 cc initially, but only 20 cc exhaled
Establishing FRC, within a few hours after birth
Surfactant is present to decrease surface tension
If not can lead to RDS (respiratory distress syndrome) |
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Prenatal history |
Risk factors Persings, Chapter 13 |
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High Risk moms |
Younger than 16, older than 40
History of previous births
Previous caesarian section, miscarriages, pre and postmature delivers, fetal/neonatal deaths
Smoking, drug use, alcohol abuse, diseases
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High Risk Labors |
Prolonged
Delayed birth after PROM (premature rupture of membrane)
Placental dislocation
Meconium stained amniotic fluid
Maternal medications |
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Maternal disorders |
Toxemia
Pre eclampsia , increased blood pressure
Eclampsia: increased blood pressure with convulsions |
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Uteroplacental insufficiency (UPI)
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Causes: pre and post maturity; maternal heart and pulmonary disease
Results of UPI: :Lack of growth (IUGR) intrauterine growth retardation :Death :chronic fetal asphyxia :Meconium stained amniotic fluid |
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Diabetic mom (page 22) |
Complicates: 4% of US pregnancies
Mild form (controlled by diet): large infants (LGA) with no other problems. Infants have delayed lung maturation INFANTS HAVE DELAYED LUNG MATURATION
Insulin dependant: normal or small (SGA) babies with higher risk for hypoglycemia. Infants have increased lung maturation HYPOGLYCEMIA, INFANTS HAVE INCREASED LUNG MATURATION |
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diabetic complications |
Mom has it, mom at risk for chronic hypertension and pre: exlampsia
Mom has it and baby has problems with Prematurity
Large infants with possible birth injury: shoulder displacement
Hyperinsulinemia: infant at risk for hypoglycemia after birth
UPI due to maternal hypertension, leading to hypoxia |
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Infants of diabetic moms (IDM) |
Classic presentation: fat, large infant
If UPI present, there will be a decrease in fetal growth
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Smoking |
CO interferes with O2 supply with fetus
Nicotine crosses placenta (greater than 15 % higher than maternal levels)
Causes developmental delays
Danger of premature delivery
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Alcohol |
Freely crosses placental barrier O.5- 2 per 1000 births :1 in 9 women report binge drinking during pregnancy :1 in 5 women report drinking during pregnancy Most problematic in 1st tirmester
FETAL ALCHOHOL SYNDROME
the lifetime cost for one individual with FAS in 2016 was estimated to be 2.5 million $ |
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Drugs as a risk factor |
Sedatives: depress respirations. Poor muscle tone, trouble breathing/feeding after delivery
Narcotics: tremors, dyspnea, seizures, death from withdrawal, baby born addicted
Cocaine, causes placenta to detach too sooon. Causes bleeding, preterm birth and fetal death |
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Torch syndrome materanl infections page 24 |
Toxoplasmosis Others Rubella Cytomegalovirus Herpes
ALl have similiar clinical manifestattions, so all grouped together |
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Toxoplasmosis (cat litter disesase) |
Protozoa found in cat feces or eating raw meat
Mother may be asymptomatic or fluish
Can cause congenital defects
Diagnosis with antibodies in blood serum |
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RUbella |
Preventable if mom is vaccinated before conception Highly contagious viral illness Characterized by rash, swollen glands and join pain May be asymptomatic Affects fetus in first 5 months Low body weight |
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cytomegalovirus (CMV) |
member of herpes family pregnant healthcare personnel should NOT treat infants with CMV Spread by person to person contact mom may be aymptomatic |
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Herpes simplex type 2 |
secually transmitted acquired by fetus during birth via contact with genital secretions or following rupture of the membrane c section preferred (if active) Can affect CNS, skin, and has a high mortality if disseminated in the lung |
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HIV infection |
Neonatal HIV is more commonly from infected mom Risk factors for prenatal infections :Mom is IV drug user :Infant exposure to infected blood products or breast milk |
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Transmission of HIV |
during delivery by coming in contact with moms blood breast feeding transufsion with infected blood trasnplacental transfer (not all hiv moms pass the virus) Zidovudine (AZT) antiretroviral drug, given prior too delivery to mom, then for 6 weeks to infant to reduce incidence of HIV coplications |
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Manifestations of HIV |
failure to thrive (FTT) Developmental delay Infection risks Treat with AZT, pentamidine (antimicrobial) to prevent and treat pneumocystis, steroids) |
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Group B streptococcus |
Risk of death if premature delivery or PROM Vaginal cultures at 35 to 37 weeks Penicillin/ ampicillin |
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Multiple gestations |
2 or more |
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Complications of multiple gestation |
Premature labor and delivery IUGR (intrauterine growth retardation): if identical twins, one twin will have a smaller placenta Breech/ abnormal presentations during delivery (head up butt down) Twin transufation syndrome (one twin bigger than other twin |
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Twin transfusion syndrome |
One twin (larger) Polycythemia,, CHF, hyperbilirubinemia Second twin (smaller) Anemic, shock from blood loss |
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Placental problems |
Placental previa (to low in the uterus) Rather than being attached to the upper wall of the uterus, the placenta lies low in the uterus, partially or completely covering the cervix |
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Placenta previa: complications for baby and mom |
Associated with blood loss IUGR due to poor placental perfusion Fetal asphyxia Life threatening hemorrhage Cesarean delivery may be required |
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Abruption placenta |
Tearing of the placenta away from the uterine wall prior to delivery Mom can fall, or rear ended in a car accident, potential to rip placenta away from uterine wall |
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Abruption placenta |
Normally attached placenta separates prematurely causing labor to begin Maternal mortality up to 10 %, infant mortality up to 50% Can be partial or complete BLeeding can be visible or concealed Risk if severe hypoxia and blood loss |
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Abruption Placenta |
Maternal hypertension Trauma Shortened umbilical cord Uterine abnormalities Excessive number of previous pregnancies |
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Abruption placenta risks for baby |
prematurity Hypoxia Hemorrhage |
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Abruption placenta treatment |
Replaced blood volume to mother Mother positioned on lateral position to allow maximum placental circulation Intensive monitoring Emergency C section delivery in cases of maternal shock or fetal distress |