LC Exam 2: Placenta Flashcards
3rd trimester anatomy
Fetal side: smooth, amnion fused to chorion
Separated by chorionic villi
Maternal side: basal plate
Cross sections reveal many more capillaries, less fibrous cores
3rd trimester anatomy
Fetal side: smooth, amnion fused to chorion
Separated by chorionic villi (capillaries, exchange)
Maternal side: basal plate
Cross sections reveal many more capillaries, less fibrous cores
Functions of the placenta
Support growth and development
Transport (nutrients, O2, CO2)
Respiration (2 arteries, 1 vein)
Endocrine
Hepatic (glycogen/FA storage, metabolism, waste)
Immune (transport maternal IgG, IgM can’t cross)
Skin: temperature regulation, barrier
Steroid production by maternal-fetal-placental unit
Progesterone production suppresses contractions
E2 production requires MFP
Placenta lacks P450c17, 16a-hydroxylase
Fetus lacks P450 aromatase, 3ßhyrdroxsteroid DH
Amniotic fluid secretion
Necessary for pulmonary and MSK fxn
Oligohydramnios
Rupture of membranes
GU congenital abnormalities
Nephrotoxic drugs (ACEI, NSAID)
Poor placental perfusion (maternal cardio dz)
Trophoblast invasion
Initially: syncytiotrophoblasts
Interstital: cytotrophoblasts (all endo and 1/3 myo)
Endovascular: cytotrophoblasts into spiral arteries, change pressure profile
hCG functions
Marker of pregnancy (peak around 10)
Decline due to increased release of progesterone
Regulates trophoblast differentiation to syncytio/cyto
hCG functions
Marker of pregnancy (peak around 10)
Responsible for morning sickness
Decline due to increased release of progesterone
Regulates trophoblast differentiation to syncytio/cyto
Elevated in pregnancies with trisomy 21
human Placental Lactogen
Produced by sCTB
Shifts maternal system towards fatty acid metabolism
Leaves carbs available for fetus
Creates insulin resistance (gestational diabetes)
Placental Growth Hormone
Similar to pituitary GH
Clinical implications of IgG transport
Rh attack of fetus
IgG to flu (maternal flu vaccine)
IgG to Tdap
Maternal autoimmune disease
Polyhydramnios
Neural tube defects, esophageal atresia Gestational diabetes (esp. uncontrolled)
ßhCG producing syndromes
Pregnancy
Ectopic
Trophoblastic dz (very high levels, >100,000 at 6wks)
Discriminatory zone
Correlate US findings with hCG levels
5-6 weeks = 1,500
7 weeks = 4,000
Ectopic pregnancy risk factors
Most common: PID Endometriosis Surgical adhesions (tubes or appendectomy)
Gestational Trophoblastic Disease
Benign or malignant
Form from cells that would have become placenta
High ßhCG
Molar pregnancy
Mom DNA -> embryonic
Dad DNA -> placental
Too much Dad -> molar pregnancies
Complete mole: diandric diploid: 46XX or XY
1 sperm + empty egg = XX, 2 sperm = XX or XY
Partial mole: diandric triplpoid: 69XXY
2 sperm + 1 egg
Complete mole on ultrasound and characteristics
Snowstorm appearance
Cystic space with NO fetal parts, grape like vesicles
No mom DNA = no fetus, lots of dad = placental
Hydropic villi
Diffuse, circumferential proliferation around hydropic villli
Increased risk of recurrent/invasive GTD
Increased risk of choriocarcinoma
Tx: curettage
Therefore intense follow up: monitoring ßhCG levels, must be on contraception (MTX if detected)
Partial mole on ultrasound and characteristics
Fetal tissue present Some villi hydropic, some normal/fibrotic Villious inclusions Focal proliferation around villi Minimal risk for choriocarcinoma
Gestational choriocarcinoma
Derived from placental tissue
Preceded by complete mole>partial mole>nml preg
Widely metastatic (usually lung), invade blood vessels
Biphasic (synctio/cyto) with hem/nec
NO chorionic vili
Responds well to chemo (high rate)
Placental Site Trophoblast Tumor
Neo prolif of extravillous trophoblast (not synctio/cyto)
Sheets/chords of trophoblasts b/t muscle fibers
Umbilical cord insertions
Eccentric (normal, on fetal side) Marginal insertion (on edge, fully covered) Velamentous (on edge, exposed for some length -> at risk for intermittent hypoxia)
Cord size/weight
>75cm = long Higher risk for knots, nuchal cord, etc <30cm = short Associated with decreased fetal movement/neuro problems <10th%ile in weight = fetal problems Too heavy = material diabetes
Cord infections
Candida (yellow spots, with hyphae) Necrotising funisitis (barber shop pole)
Membrane insertion
Normal = margin of disc Circumvallete insertion - less room to move Fetus papyraceus (disappearing twin)
Listeria infection
Acute, abcess formation in placental parenchyma
Categories of placental injury
Inflammatory (actue chorioamnionitis, chronic villitis, deciduitis)
Fetal vascular supply (maldevelopment, obstruction, rupture)
Maternal vascular supply (maldevelopment, obstruction, rupture)
Acute chorioamnionitis
25% live births, 75% premies
Infection in chorion, PMNs in fetal membranes (G.B.S)
Ascending infection - related to PROM
Chronic villitis
ToRCHeS (transplacental, hematogenous) Toxoplasma Rubella CMV HSV/HIV Syphilis
Villitis of unknown etiology
Partial autoimmune attack by maternal lymphs
High recurrence risk
2/3 IUFD
Fetal vascular supply problems
Meconium (never normal <36 GA, toxic to smooth muscle) Intervillious thrombi (laminated appearance, KB test)
Kleihauer-Betke test
Quantification of fetal RBC in maternal circulation
Bad if >20% of fetoplacental volume
Maternal vascular supply problems
Placental infarct
Collapse of villi
<10% - no effect
15-20% has effects on fetus
Placenta accreta
Implant of placenta in myometrium
Heavy bleeding
Prior C-section is predisposing factor
Often = hysterectomy
Placenta increta vs. percreta
INVADE myometrium
PENETRATE serosa
Placenta previa
Cover os
3rd trimester bleeding
Indication for C-section
Preeclampsia: def and risk factors and tx
Hypertension, proteinuria, edema >20 GA
Risk factors: FHx, pre-existing dz, previous pre-e preg
No trophoblastic remodeling of vessles (higher pressure, thick walled)
Tx: Deliver
Preeclampsia: fetal sequale
Still birth risk
IUGR + premature birth
Hypoxia, neuro injury
CAD/CVA risk as adults
Preeclampsia: maternal sequale
Abruption, DIC, stroke
Chronic HTN
Organ failure: liver, kidney, pulm edema
Abruptio placenta
Separation of placenta from decidua prior to delivery
Still birth
3rd bleeding, fetal insufficiency
Spontaneous abortion
Miscarrage before 20 weeks
1st: chr abnmlaties
2nd: structural, placental, infection
3rd: placental
IUGR: symmetric vs asymmetric
Sym: genetic
Asym: macrocephaly, oligohydramnios (poor kidney development)
Monosomy X
Turner’s syndrome
Often 1st SAB
Trisomy 21
SGA Round/flat face with palpebral fissures Transverse palmar crease Heart (ASD), GI abnmlities Pancreatic, bone marrow fibrosis (ALL risk)
Trisomy 13
Pateau SGA Polydactly, facial defects Cutis aplasia Heart/brain defects Pancreato-splenic fusion
Trisomy 18
Edwards SGA Rocker bottom feet Renal fusion Omphalocele
Triplody
69 XXX or XXY Diandric (mole) Digynic (non-molar) Incompatable with life Severe IUGR Syndactly
Fetal hydrops
Immune: Rh reactions (20%)
Non-immune: infectous (80%)
