The placenta and Umbilical cord Flashcards
AKA TROPHOBLAST, also called CHORIONIC FRONDOSUM
Highly vascular, 2-4 cm thick
Transfers nourishment, removes waste, produces hCG
Divided into 2 portions: Fetal and maternal portions NEVER cross
Normal placenta
DECIDUA BASALIS
▪ Consists of Cotyledons
Maternal portion
▪ Major functioning unit= chorionic villi
▪ Consists of a fused layer of amnion and chorion
Fetal portion - chorionic frondosum and chorionic plate
Circumvalle succenteriate chorionagioma placenta previa placenta abruption abnormal adherence
Placental variants
Chorion does not extend to the edge (elf shoe)
• May predispose to early separation from UT wall, threatened Ab and bleeding
Circumvallate
- Lobe that is connected to main lobe of placenta by blood vessels
- If vessels cross internal os = vasa previa
Succenuriate / accessori lobe
● M/C benign tumor of the placenta
● well circumscribed mass near CI
● Increased vascularity
Chorioangioma
- Partial or complete coverage of cervical os
- Primary cause of 3rd trimester bleeding
- Classifications:
- Complete- covers entire internal os
- Partial- incomplete covering of internal os
- Marginal- Placenta touches the edge of the internal os
- Low lying- Placenta is within 2cm of os
- Vasa Previa- vessels overlying CX
Placenta previa
- Premature separation of placenta from UT wall after 20 weeks
- S/S: bleeding and abdominal pain
- Assoc: w/ HTN, ABD trauma, Vascular disease, cocaine or smoking
Placental abruption
Abnormal adherence of placenta tissue to UT
Risk Factors: c- section scarring and advanced maternal age (AMA)
Three classifications:
Placenta Accreta – placenta attached to Myometrium…NO invasion
Placenta Increta- Placenta invades into UT/ Myometrium
Placenta Percreta- Placenta invades UT, Bladder or Rectum
Abrnoaml adherence
***>6cm abnormal*** Thin placenta THICK placenta • IUGR Gestational diabetes • Preeclampsia Non-immune hydrops • Juvenile diabetes Congenital abnormalities Multiple gestation Rh sensitization
Placenta abnormalities
Consists of 2 arteries and 1 vein
• Measures 1-2cm in diameter
• Average length is 55cm and covered by Wharton’s jelly and amnion
• SUA (2 vessel cord) assoc. with other fetal anomalies
• Check for 2 kidneys
• Trisomy 13 and 18
• GU, CNS and heart anomalies
Umbilical cord
- Wrapping of umbilical cord around fetal neck
* 2 x around assoc. w/ fetal death
Nuchal cord
Short umbilical cord
NOT compatible with life
Lack of closure of anterior abdominal wall
Body stalk anomaly
torsion, Knotting or compression of umbilical cord can cause thrombosis= fetal death
Umbilical venous thrombosis
- Umbilical cord attaches to the membrane rather than placenta
- Assoc w/ IUGR, preterm birth and congenital anomalies
Velamentous cord
= VERTEX – head presenting
Cephalic
feet first
breech
used to determine whether head shape is appropriate
cephalic index
- Axial section at the level of the thalami falx & CSP
- 1st measurable between 10-12 weeks
- Angle os asynclitism- angle should be 90°
BPD
- Should not include scalp echoes
* Should be measured outer edge to outer edge
head circumference
- Should include soft tissue and least reliable
* Measured at level of portal vein and stomach & aorta
Abdominal circumference
• Includes only ossified diaphysis, exclude epiphyseal cartilage
** Epiphyseal ossified centers will be identified after 30 weeks**
Femur length
Designed to detect fetal asphyxia
Scored 0 or 2
o Fetal Breathing- lasts 30 sec over 30 min period
o Movement- 3 body /limb movements
o Tone- extension/ flexion
o AFI- should not exceed 5.0cm
o NST (non-stress test)- 2 acceleration > 15 bpm/15sec
Biophysical profile
- Produced by fetal kidneys, tissue, and skin
- 2-3 trimesters consists primarily of fetal urine
- Functions of fluid: cushion from injury, nutrition, movement, temperature & lung development
- Normal range- 5-22 cm
AFI
Lecithin/ Sphingomyelin (LS ratio)
-Most accurate measurement of fetal lung maturity done by amnio
fetal lung maturity
• Decreased fluid that allows a DRIPP to remain
D emise R enal abnormalities I UGR P ROM P ost dates/ preeclampsia
oligohydramnios
• Increased fluid: pocket will be ≥ 8cm • Associated with: neural tube defects, upper GI obstructions, hydrops, Trisomy 18 (from esophageal atresia), cystic hygroma, placenta, twin-twin syndrome
Polyhydramnios
o Anemia
o UTI
o Preeclampsia
o Prepartum hemorrhage
Maternal complications
o Premature or difficult delivery
o Prolapse entanglement or compression of umbilical cord
o Growth restriction due to placenta insufficiency
o Hypoxia of 1 second twin due to premature separation of placenta
Fetal complications
reabsorption of a non-viable fetus that was previously demonstrated
Vanishing twin
o Increased MSAFP
o SOB
o Increased UT size and fetal activity
o Earlier and mores severe pressure problems in pelvis
clinical finding in twin pregnancies
OF ZYGOTES / EGGS
Zygosity
“true” or identical twins (always SAME GENDER) from a SINGLE fertilized ovum by single sperm
MONOzygotic
SINGLE PLACENTA (days 10-13)
Monochorionic,monoamnitoic
SINGLE PLACENTA, 2 amnions (days 5-10 after conception)
Monochorionic, Diamnotic
fraternal” twins from separate ova & separate sperm (day 5)
** dizygotic twins will ALWAYS have 2 placentas, 2 amnions,& 2 chorions
“twin peak” sign refers to Dichorionic, Diamniotic because placenta grows between sacs on TEST
Dizygotic
- Incomplete ÷ of a fertilized ovum after 13 days post-conception
- They can be joined by the chest, head, abdominal wall, pelvis or sacrum
- Cords of conjoined fetus have between 2-6 vessels
conjoined twins
• MONOzygotic twin severely malformed, acardiac and often anencephalic twin is perfused by the normal twin
• Normal twin supplies blood to malformed twin.
• SONO: POLY
o Pump/normal twin=hydrops fetalis
acardiac twins
• MONOzygotic twins w/ shared monochorionic placenta (cross transfusion of vascular supply of each twin to the placenta) (ARTERY TO VEIN ANASTOMOSIS)
o Donor twin- ( the stuck twin)
▪ OLIGO, small for dates and restricted movement
o Recipient twin-
▪ POLY, ascites, Hydropic enlarged liver, heart and kidney
twin to twin transfusion syndrome (TTTS)
Passage of thromboplastic material/blood clots from a dead MONOCHORIONIC twin to remaining live twin through shared intra-placental vessels
twin embolization syndrome
• Fetus weighing below 10th percentile
• D/X: the HC/AC ratio is abnormal in approx 2/3 of all restricted fetuses
• Sono: OLIGO, grade 3 placenta & delayed ossification of bones
• ETIOLOGY OF IUGR:
O Maternal: HTN, diabetes, renal disease, alcohol/ drug abuse, anemia, smoking or mult gestations
O Placenta: SUA, plac insufficiency, infarcts & hemangiomas
O Fetal: genetic or chromosomal defects, intrauterine infection
IUGR
O Etiology: often genetic as result of 1st trimester insult
O Fetus is proportionately small throughout pregnancy (2 weeks)
o SONO: oligo, early mature placenta, low BPP
symmetric IUGR (25%)
o Occurs in last 8-10 weeks of pregnancy
o Hemodynamic pattern protects brain = “brain sparring”
o AC measures > 2 weeks behind HC; head is usually normal
o SONO: oligo & mature placentas
Ayssmetrical IUGR (75%)
Used to identify growth restriction, hypoxia and/or distressed fetus
Doppler Evaluation
NORMAL: as gestation progresses, INCREASE in diastolic flow velocity
which reflects a DECREASE in placenta resistance (RI > 0.8)
S/D ratio > 2.6 after 30 weeks = ABNORMAL
Absence or reversed diastolic flow in the UA is NOT GOOD!
CI @ placenta = LOW resistance & CI @ fetal abd. = HIGH resistance
Umbilical artery
LOW resistance in 2nd & 3rd trimester is NORMAL
Appearance of “notch” is ABNORMAL & predictor of placenta insufficiency leading to IUGR
Uterine artery
- Determines fetal anemia using velocity of PI
- Checking IUGR use S/D ratio & MCA s/b ↑ than umbilical artery
- In a hypoxia fetus, vessels become enlarged from “brain sparing”
- Normal values > 4 throughout pregnancy w/ LITTLE diastolic flow
- Use near field vessel for Doppler w/angle @ 5° or less 0° is best
MCA- Middle Cerebral Artery “Circle of Willis” (closest to orbits)
• 2 or more fluid filled fetal body cavities & skin thickening
• 2 Categories:
o IMMUNE- caused by Rh incompatibility (mother)
o NON-IMMUNE- caused by abnormal FETAL fluid balance
• Fetal GU, cardio, chromosomal, cord/placenta abnormalities, malformation or TORCH infections
• SONO: pericardial effusions, POLY, ↑ liver, heart, UV, skin & THICK placenta (> 4 cm)
• “ANASARCA” – skin edema
Hydrops fettles
- Puncturing the VEIN of the umbilical cord
* Used as a treatment for immune hydrops
PUBS (Percutaneous Umbilical Blood Sampling)
• During 2nd & 3rd trimester sono appearance dependant upon when demise occurs after fetal examination
o ROBERT’S SIGN- echogenic foci (gas) in pulmonary vessels or in abdomen
o SPALDING SIGN- overlapping skull bones
** IMAGES of both on exam & BOTH are visualized 1 WEEK AFTER DEMISE**
FETAL DEMIWE
Sequence- single defect leading to the development of other defects
Syndrome- 2 or more embryological, unrelated anomalies occurring together
affecting 2 or more different organs or body areas
Association- Non-random occurrence of 2 or more defects
FETAL SYNDROMES
• Bands of tissue the trap/ encircle parts of the fetal body in early pregnancy
o Limb defects: amputation, club feet, constrictions, pseudosyndactyly
o Craniofacial defects: encephalocele, facial cleft, asymmetric anencephaly
o Visceral defects: gastroschisis, ectopia cordis
AMNIOTIC BAND SYNDROME
• Chromosomal abnormalities w/ multiple anatomic problems
o HOLOPROCENCEPHALY
o IUGR, POLY, agenesis of corpus callosum, micrognathia, cleft lip/palate
o Omphalocele, VSD, GU abnormalities, polycystic kidney
TRISOMY 13 PATAU’S SYNDROME
• Karyotype abnormalities
o Clenched hand w/ finger/thumb crossover (clinodactyly)
o VSD, ASD, CP cysts, ↑ cisterna magna/ Dandy-Walker
o Micrognathia, dolichocephaly, IUGR, POLY (3rd trimester)
o Omphalocele, hydro, diaphragmatic hernia
TRISOMY 18 (EDWARDS SYNDOME)
• Malformation w/ mental retardation & characteristic physical appearance
o Nuchal fold measuring > 6mm between 15-21 weeks
o VSD, ASD, mild ventriculomegaly
o Absent or small nasal bone, duodenal atresia, renal pylectasis & echogenic bowel
TRISOMY 21 (DOWN SYNDROME)
• Malformation syndrome of complete or partial absence of the X chromosome in phenotype females
o Cystic hygroma, lymphadema
o Cardiac anomalies, horseshoe kidney or uni-renal agenesis
TURNERS SYNDROME (XO KARYOTYPE)
• “Cloverleaf skull”
KLEEBATTSCHADEL SYNDROME
• Related to autosomal recessive inheritance
o Encephalocele & polycystic kidneys
o Cleft lip, polydactyly
MECKEL-GRUBER SYNDROME
BECKWITH-WEIDMAN SYNDROME
• Group of congentital disorders
o Macroglossia, gigantIsm & omphalocele
o Placenta ↑ or chorioangiomas, cardiac malformation & post natal Wilm’s tumor
BECKWITH-WEIDMAN SYNDROME
• Association of 2 major defects: Omphalocele & ectopia cordis, along with 3 other defects involving lower sternum, diaphragm or pericardium
PENTOLOGY OF CANTRELL
POTTER’S SYNDROME
• BILATERAL renal agenesis & OLIGO
POTTERS SYNDROME
• extra set of chromosomes
TRIPLOIDY
