Exam #3 Flashcards
ch. 47-52
MSD: meaning and formula
*Mean Sac Diameter
MSD = L + W + H / 3
TA MSD: __ mm should see yolk sac
20 mm
TA MSD: __ mm should see embryo
25 mm
In a TA MSD, a normal yolk sac should never exceed _ mm
6 mm
In a TA MSD, what should be suspected if you do not see an embryo by 25 mm?
anembryonic pregnancy
(gestational sac is empty)
TV MSD: __ mm should see the yolk sac
8-10 mm (acc. to Radiopaedia)
TV MSD: __ mm should see embryo
16-18 mm
CRL
*Crown Rump Length
- the most accurate measurement in in 1st trimester to predict due date
What are the two main parameters for gestational dating in the 1st trimester?
- crown rump length
- mean sac diameter
FHT
*Fetal Heart Tone/Rate
- seen with TV at 5-6 weeks
What is the normal heart range?
100-180 bpm
Tachycardia is heart rate…
over 180 bpm
Bradycardia is heart rate…
under 100 bpm
In the 1st trimester of pregnancy, what indicates a poor pregnancy outcome?
a heart rate <90 bpm
Ductus Venosus
- umbilical vein –> IVC during fetal development
- blood bypasses the liver
Ductus Arterious
- fetal pulmonary artery –> aorta during fetal development
- blood bypasses pulmonary circulation
Foramen Ovale
- blood moves from R. –L. atrium
- blood bypasses lungs
Zygote
the union of M and F cell at fertilization
Gamete
M and F germ cell
Morula
16 cell ball
Blastocyst
early stage of an embryo that develops 5-6 days after fertilization
Trophoblast
- the outer layer of cells of the blastocyst
- provides nutrition to developing embryo
Trophoblast: two layers
- cytotrophoblast: inner layer
- synctiotrophoblast: multilayered
- fx: prod. BhCG, keeps Corpus Luteum growing
Eventually the trophoblast cells become the _____
placenta
Early in the pregnancy, a placenta is known as the _____
chorion
Syncytiotrophoblast: word breakdown
- Syn: together
- cytio: of cells
- tropho: nutrition
- blast: bud
Amnion
the sac which houses the embryo/fetus
By 16 weeks, the amnion should fuse with
chorion
Decidua
the specialized layer of endometrium that forms the base of the placental bed
Decidua Basalis
- myometrial side of the concepts
- site of future placenta
Decidua Parietalis
- aka Decidua Vera
- lines UT cavity
- loc. on the non-implantation side of ut; opp of decidua basalis
Decidua Capsularis
closes over and surrounds the blastocyst (gestational sac)
Chorion Laeve
part of chorion in contact with decidua capsularis
Chorion Fronosom
helps form the placenta, which provides nutrients and oxygen to the fetus
hCG
produced by?
detected when?
stimulates.?
growth & plateau rate?
- prod. by trophoblastic layer of blastocyst
- detected 10 days after implantation
- stimulates the corpus luteum cyst on the ovary
- ## doubles every 2 days; plateaus at 8 wks
hCG can be elevated due to:
incorrect dates, GTD, twins
hCG can be too low due too:
incorrect dates, EP, fetal demise
AFP-
what does it stand for?
where is it manufactured?
how can it be detected?
- alpha feto protein
- by the fetus in the liver, GI tract, and yolk sac
- detected in maternal blood
What conditions show increased AFP level?
- anencephaly
- spina bifida
In TA, the levels of hCG in blood should be…
1800 mIU/ml
In TV, the levels of hCG in blood should be…
1000 mIU/ml
When is the embryonic period?
4-10 weeks
When does the fetal period start?
10-11 weeks
Gestational Age is measured from…
LMP
is a.k.a “Menstrual Age”
Conceptual Age is measured from the…
date of conception
is a.k.a “Embryonic Age”
Decidual Reaction
*seen in in early IUP (& EP)
- thickening of the endometrium around the gestational sac
Double Decidual Sign
- two concentric rings surrounding the anechoic gestational sac
Double Bleb Sign
two sacs (amnion and yolk sac) side by side
Pseudogestational Sac
false sac; assoc. w/ EP
Ectopic Pregnancy-
what is it?
most common loc.?
what are some susp. indicators?
most common findings?
- a pregnancy outside the womb
- ampulla of salping
- “bagel sign”, pseudogestational sac, lowered BhCG
- # 1 adnexal mass; pain & free fluid
EP w/in the intersitual or ___ region can lead to _____ _____ and even _____
- cornua
- massive hemorrhage
- death
A cervical pregnancy can lead to a _ because of __ _____.
- hysterectomy
- uncontrolled bleeding.
Gestational Trophoblastic Disease
*aka a molar pregnancy (hydatidform mole)
- two types:
- complete mole
- partial/incomplete
GTD- Complete Mole
what is it?
patient presentation?
US appearance?
which cysts may be present?
- sperm fertilizes an empty egg (no nucleus)
- large for gest. age, HIGH BhCG (1000,000)
- UT cavity like a bunch of grapes
- theca lutein cysts in ovaries
GTD- Partial Mole
what is it?
placental changes?
fetal tissue is..?
- two sperm fertilize one egg
- focal cystic changes & enlarged placenta
- incomplete fetal tissue visualized
- vv uncommon to have twins: 1 normal & 1 molar pregnancy
Invasive Mole
*aka: Chorioadenoma Destruens
<1% of all molar pregnancies
- MALIGNANT GTD
- molar tissue invades myometrium
- enlarged UT
- appearance is similar to a missed AB.
Choriocarcinoma
- not considered a true mole
- MALIGNANT UT TUMOR
- origin. in cells of chorion
-THERES MORE TO PUT
Situs
site or position
Situs inversus
major visceral organs are reversed from their normal position
Nuchal
neck
Nuchal Translucency in 1st Tri..
- b/w 11-13 wks & 6 days
- should be <3 mm
Nuchal Fold in 2nd Tri..
- should be 6 mm
What are the functions of the Yolk Sac?
- hematopoiesis (blood creation)
- provides nutrients
- involved in development of primitive gut
Allantois
the precusor tissue that develops into the umbilical cord
Yolk Stalk
- a narrow tube present in the early embryo that connects midgut to yolk sac, through the umbilical opening
Meckelis diverticulum
- congenital abnormality
- a small pouch in the wall of the intestine, near the junction of the small and large intestines
In placental mammals, the allantois is part of and forms..
an axis for the development of the umbilical cord
Fertilization occurs how long after ovulation?
24-36 hours
What is the most common 1st trimester abnormality?
The most common sign is…
- subchorionic hemorrhage
- spotting
The umbilical cord has how many vein(s) and arter(ies)y?
- 1 vein
- 2 arteries
Why is imaging of the fetal profile important during the later 1st and the 2nd trimester?
to rule out any abnormalties of the head, incl:
- absent nasal bone
- micrognathia
- cephalocele
- frontal bossing
- nose & tongue deformities
micrognathia
small chin
cephalocele
ML protrusion of brain/meninges through skull defect
frontal bossing
enlarged forehead
Cleft Lip
Cephalic or Vertex position
presentation where:
- baby is ready for birth
- head down at CX
Breech position
where baby’s butt/feet are at CX
What are three main variations of the breech presentation?
- complete breech
- incomplete breech
- frank breech
BPD
*Biparietal Diameter
- measuring the skull diameter of a developing fetus
- outer to inner
‘leading edge to leading edge’
Falx, CSP
*Cavum Septum Pellucidum
- paired thalami
HC
*Head Circumference
- use elipse fx & encircle the skull
AC
*Abdominal Circumference
- use elipse fx & encircle abdomen
-
What are the three landmarks of AC?
ossifications:
- spine
- stomach
- left portal vein (umbilical port.)
FL
*Femur Length
- ONLY measure shaft/diaphysis
What are the three structures in the posterior fossa we are imaging?
- cerebellum
- cisterna magna
- nuchal fold
In spina bifida, what structure is effaced? & what structure is banana shaped?
- possibly effaced: posterior fossa
- banana shape: cerebellum
When imaging the lateral ventricles-
- echogenic choroid plexus w/in fluid filled ventricle
- measurement <10mm (avg. is 6.5 mm)
Naegle’s Rule for predicting-
pregnancy
LMP
EDD = LNMP - 3 mo. + 7 days
LNMP = EDD - 3 mo. + 7 days
How long is a full term pregnancy?
39-40 weeks
A human pregnancy lasts ___ days
266 days (plus or minus 10 days)
Early term:
b/w 37 wks 0 days & 38 wks 6 days
Late term:
b/w 41 wks & 41 wks, 6 days
Post term:
42 wks +
ALARA
As Low As Reasonably Achievable
Abortion
an elected termination/end to a pregnancy
Miscarriage
an unplanned loss of pregnancy
Spontaneous
Habitual
Inevitable or Imminent
