Labs Flashcards
which weeks constitute the 1st trimester?
1-13
what weeks constitute the 2nd trimester
14-26
what information can be provided by transvag US on 3rd trimester US?
presentation
layer of endo sloughed off during menstruation
functional layer
hormone produced by follicular cells
estrogen
In IVF, what stage of development is the embryo when introduced into the uterus?
blastocyst
which specific arteries empty blood into the intervillous spaces?
spiral arteries
what layer of the gastrula will differentiate into the brain cells?
ectoderm
sono appearance of DDSS
decidua parietlis and decidua capsularis (both smooth)
decidua basalis sono appearance
echogenic, heterogenous
what will be seen at 2wk GA
no gestational sac, possible thickened endo
what will be seen at 3.5-4wk GA
focal thickening of one side of endo
what will be seen at 5 wk GA
GS will be visible once MSD reaches 2-3mm
what will be seen at 5.5 wk GA
YS
what will be seen at 6wk GA
embryo adjacent to YS
what will be seen at 9wk
limb buds may be seen
transvag normal measurement of MSD with YS present at 5.5 wk
8 mm
transvag normal measurement of MSD with embryo present at 6 wk
16 mm
if MSD is larger than 8 or 16 mm without the associated structure, what does this suggest?
early pregnancy failure
in fraternal twins, what chorionicity and amnionicity are expected to be seen on sonogram
2 chorions
2 amnions
what risks are assoc with MCDA twins? (2)
shared nutrients
TTTS
what risks are associated with MCMA twins? (3)
entangled cords,
kicking
shared blood supply
what is oligohydramnios
amniotic fluid volume less than expected for GA
during fetal biometry, which femur should always be measured
in near field
why is breech position considered high risk
pinches umbilical cord
what is the threshold for nuchal translucency at the NT U/S
<3 mm
at what measurement is nuchal translucency measurement valid?
CRL 45-84 mm
a round anechoic structure is seen in the fetal head at 9 weeks. what is this? what does it become?
rhombencephalon - diencephalon
what’s nuchal cord?
where umbilical cord becomes wrapped around fetus’s neck
CRL is measuring 25 mm. what is the approx GA?
9-10 weeks
How do you measure nuchal fold?
outer-outer
somites form 3 diff layers
sclerotome
myotome
dermatome
what structure connects the two lobes of the thalamus
interthalamic adhesion
head shape would result in a long OFD and short BPD measurement
dolchiocephaly
hypotelorism
eyes too close together
micrognathia
poor development of jaw
list the five main tissue prominences and the adult structures that they become
- frontonasal - forehead/apex of nose
- maxillary - upper cheeks/upper lip
- mandibular lower cheek/ lower lip, chin
- lateral nasal - nasal ala
- medial nasal - nasal septum
what can the facial angle of the fetal profile tell us?
if baby has chromosomal abnormality
what is the purpose of the coronal nose/lips view
to check for cleft lip
what adult structures does the pharynx become?
esophagus/trachea
differences between a nuchal translucency and nuchal thickness/fold assessment
NT - anechoic space, a collection of fluid under skin of fetal neck <3 mm
thickness/fold - thickness of skin behind occipital bone <6 mm (before 22 weeks), outer to outer
