Lecture 5- Fetal period Flashcards
Placenta- What does the endometrium consist of that comes from mom
Epithelium & vascularized stroma
Placenta- what does from maternal stroma differentiate into
Decidua
Placenta- What is the maternal part of the placenta
Decidual basalis
Placenta- What is the fetal part of the placenta
The chorionic plate
Placenta- what does the chorionic plate derive from
Cytotrophoblast, syncytiotrophoblast, and parietal extraembryonic mesoderm
What is the bilaminar disc composed of
Hypoblast, Epiblast
Where is the decidua basalis
Between the embryo and myometrium
What are the 2 parts of the placenta
Decidua basalis (maternal), villus chorion (fetal)
When does the placenta separate from the uterine wall
After delivery of the baby
Identify red box on top only
When is the endometrium called the decidua
When fibroblastic stromal cells of endometrium swell into decidual cells
What is the area of the decidua basalis that is most intimately connected with the fetal parts
Decidual plate
Identify bottom arrows
What does the chorionic plate consist of
Parietal EEM, cytotrophoblast, syncytiotrophoblast
What projections from the chorionic plate increase surface area for exchange
Chorionic villi
What is the most mature developmental stage of a chorionic villus containing fetal capillaries derived from parietal EEM?
Tertiary villus
What do chorionic villi anchor to
Chorionic plate and cytotrophoblast shell
What covers the top part of the placenta
Cytotrophoblastic shell
What is the most efficient at gas transport
Fetal endothelium and syncytiotrophoblast
What does the placental barrier block
Large complex molecules, peptide hormones, bacteria
What does the placental barrier allow to cross
Gas/nutrients/waste, steroid hormones, some antibodies, medications/ drugs (alcohol), viruses
What can the passage of an Rh antigen cause
Hemolytic disease of newborn (erythroblastosis)
What is it called when the placenta covers the cervix
Placenta previa
How do you diagnose placenta previa
Ultrasound
What is placenta accreta?
Attachment to the myometrium
What is placenta increta
Invasion of the myometrium
What is placenta percreta
Growth through the uterus to adjacent organs of the body
Rate the placenta accretas in order from least to worst
Accreta, increta, percreta
What does the umbilical cord contain
1 vein (blood to fetus), 2 arteries (blood to placenta), stalk of yolk sac, allantois
By week 12 amnion and chorion contact and fuse into _____
Amniochorionic membrane (ACM)
Rate the placenta accretas in order from least to worst
Accreta, increta, percreta
Define PROM (premature rupture of the membranes)
Rupture of the ACM before uterine contractions begin
Define preterm PROM (PPROM)
ACM ruptures prior to 37 weeks of pregnancy. PPROM is a common cause of preterm labor
Define Polyhydramnios
Excessive amniotic fluid volume caused by GI malformations preventing fetus from swallowing
Define oligohydramnios
Low amniotic fluid volume linked to PROM or renal issues preventing urination
What causes increased occurrences of twinning
Increased maternal age, ARTs (assisted reproductive technologies)
Dizygotic twins are called what
Fraternal twins
Why do dizygotic twins have unique DNA
Because of the simultaneous shedding of 2 oocytes each fertilized by a different sperm
What are 2 characteristics of a dichorionic/ diamniotic (DCDA) twins
Each twin has their own chorion/ placenta and amnion
What kind of twins is this
Dizygotic
What is another term for monozygotic twins
Identical twins
Monozygotic twins originate from what
From single zygote that can split at various stages of development
What are characteristics of Dichorionic / diamnionic (DCDA)
▪ Split at two-cell stage, leading to two blastocysts
▪ Each twin has own chorion/placenta and amnion
What are characteristics of Monochorionic / diamnionic (MCDA)
Embryoblast (inner cell mass) splits into two
▪ Shared chorion/placenta but separate amnions
▪ Most common
What are characteristics of Monochorionic / monoamnionic (MCMA)
▪Early bilaminar disc splits
▪Shared chorion/placenta and amnion
Identify each set of twins
How many weeks is a full-term pregnancy
38 weeks fertilization age, (40 weeks gestational age, as determined by LNMP)
When does the rupture of fetal membranes occur
At full-term or during labor
What can a transabdominal ultrasound assess
Measures fetus, assess placenta, estimate fetal mass to test for intrauterine growth restriction (poor outcomes for fetus with very low weight)
What can a maternal serum screening assess
Triple screen test (must also confirm with amniocentesis)
▪ Organ defects
▪ Molar pregnancy
▪ Ectopic implantation
▪ Hormone deficiencies
▪ Down’s syndrome (trisomy 21)
Ultrasound- guided needle sampling is called what
Amniocentesis (amniotic fluid test)
What does US guided needle sampling (amniocentesis) test for
▪ Low risk to fetus
▪ Fluid contains fetal cells,
proteins, hormones,
metabolites that can be
analyzed
What does maternal serum screening test-(Cell-free fetal DNA)
Sex of baby, downs syndrome
What does maternal serum screening test for
Sex of fetus, downs syndrome
What does an endoscopic (fetoscopy) exam test for
▪ Very invasive
▪ Reserved for
extreme cases
What is one downside of a maternal serum screening (triple screen test)
Lots of false positives
