LC Exam 2: Placenta Flashcards by Cameron Niswander

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

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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

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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

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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

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Amniotic fluid secretion

Necessary for pulmonary and MSK fxn

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Oligohydramnios

Rupture of membranes
GU congenital abnormalities
Nephrotoxic drugs (ACEI, NSAID)
Poor placental perfusion (maternal cardio dz)

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Trophoblast invasion

Initially: syncytiotrophoblasts
Interstital: cytotrophoblasts (all endo and 1/3 myo)
Endovascular: cytotrophoblasts into spiral arteries, change pressure profile

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hCG functions

Marker of pregnancy (peak around 10)
Decline due to increased release of progesterone
Regulates trophoblast differentiation to syncytio/cyto

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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

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human Placental Lactogen

Produced by sCTB
Shifts maternal system towards fatty acid metabolism
Leaves carbs available for fetus
Creates insulin resistance (gestational diabetes)

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Placental Growth Hormone

Similar to pituitary GH

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Clinical implications of IgG transport

Rh attack of fetus
IgG to flu (maternal flu vaccine)
IgG to Tdap
Maternal autoimmune disease

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Polyhydramnios

Neural tube defects, esophageal atresia
Gestational diabetes (esp. uncontrolled)

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ßhCG producing syndromes

Pregnancy
Ectopic
Trophoblastic dz (very high levels, >100,000 at 6wks)

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Discriminatory zone

Correlate US findings with hCG levels
5-6 weeks = 1,500
7 weeks = 4,000

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Ectopic pregnancy risk factors

Most common: PID
Endometriosis
Surgical adhesions (tubes or appendectomy)

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Gestational Trophoblastic Disease

Benign or malignant
Form from cells that would have become placenta
High ßhCG

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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

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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)

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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%)