Obstetrics Flashcards
1st trimester measurement
Crown rump length(may include nuchal translucency)
Energy output from Doppler can be ___ times more intense than that of Bmode us
10-15 times
Effects most significant in 1st trimester
Potential cavitation and tissue disruption
Embryonic period
0-10 weeks
Read
Tiny well-defined cystic structure implanted within the echogenic decidua
Intradecidual sign (4.5 weeks)
Visualization of three layers of decidua early in pregnancy
Double decidua sign
Normal sac has an echogenic border of
Greater than 2mm
1) Lines the endometrial cavity
2) Covers the gestational sac
3) Contributes to the formation of the placenta at the site of implantation
1) Decidua Vera
2) Decidua Capsularis
3) Decidua Basalis
Thin stalk connected to the mid-gut of the embryo.
Meckel diverticulum
Vitelline duct (omphalomesenteric duct)
Earliest site of blood cell formation in the embryo
Yolk sac
Embryo develops within the ___ while the yolk sac develops in the ____
Amniotic cavity; chorionic cavity
Earliest cardiac activity can be detected at
Approximately 6 weeks
Fetal urine production begins at
10 weeks
Fusion of amnion and chorion at
14-16 weeks
Measurements
1) before embryo
2) embryo is visualized
1) MSD (mean sac diameter)
2) CRL (crown rump length)
Hindbrain forms a prominent structure that becomes the normal 4th ventricle
6-8 weeks
___ Midgut herniates into the base of the umbilicus forming a physiologic omphalocele ____
9-11 weeks; 6 - 9 mm in size
CRL is useful until
12 weeks GA
BPD is measured on an axial image of the fetal head at the level of
3rd ventricle and thalamus
Parameters to assess for acute hypoxia (4)
Reactive fetal heart rate
Respiratory activity
Gross motor movements
Fetal tone
Parameter for chronic hypoxia (1)
Amniotic fluid volume
Placenta
1) 1st apparent at
2) disk like at
3) finely granular and homogenous at
1) 8 weeks
2) 12 weeks
3) 18 weeks
MC tumor of the placenta
Chorioangioma
Normal umbilical cord
2 arteries
1 vein
