ob weeks 11-14

1st trimester uses of ultrasound

confirm viability, date pregnancy, mult gestations, complications/defects

limb buds visible by … weeks

8

anechoic area in the fetal head …, …brain, first seen at … weeks

rhombencephalon, hind, 8.5

what type of abnormalities are going to be seen during a 1st tri scan

gross

biggest sign of an abnormality during the 1st tri

major difference in size and dates

gestational age aka … age

menstrual

embryonic period rage

conception till 10-13 weeks

fetal period rage

10-13 weeks - birth

first trimester rage

conception - 13.6 weeks

intracranial structures: forebrain aka…, midbrain …, hindbrain …

prosencephalon, mesencephalon, rhombencephalon

prosencephalon: anterior portion forms…, posterior forms …

lateral ventricles, 3rd ventricle

rhombencephalon: seen at … weeks, appearance, forms the …

8, anechoic circle, fourth ventricle

1st trimester choroid plexus appearance

fills lateral ventricles

4 areas scanned during 1st trimester scan

nasal bone, nuchal translucency, ductus venosus, tricuspid

nasal bone appearance 1st tri, sign, absence points to…

2 echogenic lines below forehead, =, trisomy 21

nuchal translucency: area between … and …, maximum thickness, large points to…, what membrane should NOT be included in the measurement

skin, soft tissue of cervical spine, 3 mm, trisomy 21, amnion

nuchal translucency requirements: date range, CRL (range, mm), plane, fetus position, should see (2); should NOT see (3)

11-13.6, 38-84 midsagittal, horizontal, 3rd and 4th ventricles, tip of nose; ribs, stomach, heart

ductus venosus: connects … and …, normal flow velocity systole, diastole, A wave (right after diastole, atrial contraction), predicts …, becomes … after birth

umbilical vein, ivc, high, high, forward, heart failure, lig venosum

fetal tricuspid flow: performed between …-… weeks, heart view, tricuspid is on the … side, looking for …, shown by … cm/sec + velocity for over ½ cardiac cycle, points to …

11-13.6, 4 chamber, right, regurgitation, 80 trisomy 21

defects that can bee seen in the 1st trimester

cns, face, neck, cardiac, respiratory, gi, genitourinary

missing fetal skull

exencephaly

what 2 scary looking findings may be normal

hindgut herniation, abdominal cysts

megacystitis: ultrasound appearance, sign, effect on devlopment

huge bladder, keyhole, hypoplastic