Second/Third Trimester OB
37%of exam
Protocols + Procedures
24%of exam
Scan TechniqueMeasurementsDocumentationSafety ALARA
Gynecology
19%of exam
First Trimester OB
12%of exam
Early PregnancyCRL NTViabilityEctopic
Physics + Instrumentation
8%of exam
DopplerHemodynamicsArtifactsBioeffects
Quick Facts
- Exam
- RDMS OB/GYN
- Questions
- 170
- Time
- 3 hours
- Pass
- 555 scaled
- Scale
- 300 to 700
- Fee
- $275
- Vendor
- Pearson VUE
- Prerequisite
- SPI required
Fetal Biometry
BPD HC AC FL for growth
BPD: head widthHC: head aroundAC: belly girthFL: long bone
AFI vs SDP
AFI
- Four quadrants summed
- Routine screening
- Five to twenty five
SDP
- Single deepest pocket
- Twins preferred
- Two cm minimum
Sum vs deepest
Fluid Assessment Picker
- Routine third trimester→AFI(Sum four)
- Twins or oligohydramnios→SDP(Deepest pocket)
- AFI below five→Oligohydramnios(Low fluid)
- AFI above twenty five→Polyhydramnios(High fluid)
- No fluid pockets→Anhydramnios(Severe oligio)
- BPP component→Largest pocket(Two cm min)
- Membrane rupture suspect→Sterile TV exam(Pooling)
- Growth restriction workup→Doppler UA MCA(Redistribution)
Fetal Biometry
- BPD
- Biparietal diameter head
- HC
- Head circumference
- AC
- Abdominal circumference
- FL
- Femur length
- EFW
- Estimated fetal weight
- HC/AC ratio
- Asymmetry flag
- Hadlock
- Common EFW formula
- Percentile
- Growth curve rank
BPP Components
Tone move breath fluid NST
Tone: flex extendMovement: bodyBreathing: diaphragmFluid: pocketNST: heart rate
Previa vs Low-Lying
Placenta previa
- Covers internal os
- C-section delivery
- No digital exam
Low-lying
- Within two cm os
- May clear third trimester
- Follow serial scans
Covers os vs near
Fetal Anatomy Survey
- CSP
- Cavum septum pellucidum
- Ventricles
- Lateral brain fluid
- Four chamber
- Heart standard view
- Outflow tracts
- LVOT and RVOT
- Spine
- Vertebrae skin line
- Stomach bubble
- Left upper quadrant
- Kidneys
- Both sides pelvis
- Extremities
- Three bones each
Oligo vs Polyhydramnios
Oligohydramnios
- AFI under five
- IUGR rupture
- Pulmonary hypoplasia risk
Polyhydramnios
- AFI over twenty five
- Diabetes anomaly
- Preterm labor risk
Low vs high fluid
Placenta + Fluid
- Placenta previa
- Covers internal os
- Accreta spectrum
- Abnormal attachment
- Abruptio
- Premature separation
- AFI
- Amniotic fluid index
- SDP
- Single deepest pocket
- Oligohydramnios
- Low fluid volume
- Polyhydramnios
- Excess fluid volume
- BPP
- Biophysical profile score
TA vs TV
Transabdominal
- Curved probe
- Full bladder pelvic
- Later gestation
Transvaginal
- Endocavity probe
- Empty bladder
- Early detail
External vs internal
Probe Picker
- Early first trimester→Transvaginal(High freq)
- Second trimester anatomy→Transabdominal(Curved)
- Obese patient→Lower frequency TA(Penetration)
- Cervix length check→Transvaginal(Empty bladder)
- Pelvic mass TV→Transvaginal(Detail)
- Large uterus fundus→Transabdominal(Wide field)
- Fetal heart early→Transvaginal(Before CRL)
- Amniotic fluid AFI→Transabdominal(Four quadrants)
Scan Protocols
- Transabdominal
- Curved array probe
- Transvaginal
- High frequency endocavity
- Full bladder
- TA pelvic window
- Empty bladder
- TV pelvic standard
- ALARA
- Lowest practical exposure
- TI
- Thermal index
- MI
- Mechanical index
- Documentation
- Images labels measurements
Exam Logistics
- ARDMS
- Credentialing body
- SPI
- Physics prerequisite exam
- 60 day wait
- Retake interval
- 10 year cert
- CME renewal required
- CAAHEP
- Accredited program path
- Pearson VUE
- Test delivery vendor
- Scaled 555
- Approximate pass line
Simple vs Complex Cyst
Simple
- Thin wall
- Anechoic fluid
- Usually benign
Complex
- Septations solids
- Vascularity wall
- Needs follow up
Benign vs suspicious
Pelvic Anatomy
- Endometrium
- Uterine lining layer
- Myometrium
- Uterine muscle wall
- Cervix
- Lower uterine segment
- Ovary
- Follicle producing organ
- Broad ligament
- Peritoneal uterine fold
- Cardinal ligament
- Uterine artery path
- Adnexa
- Ovary tube complex
- Cul-de-sac
- Posterior pouch fluid
GYN Pathology
- Fibroid
- Benign myometrial mass
- Adenomyosis
- Endometrium in myometrium
- PCOS
- Multifollicular enlarged ovary
- Simple cyst
- Thin wall anechoic
- Complex cyst
- Septations solid areas
- Hydrosalpinx
- Dilated fluid filled tube
- Endometrial stripe
- Postmenopausal thickness
First Trimester Sequence
GS yolk embryo CRL heart
GS: five weeksYolk: five to sixEmbryo: six weeksCRL: seven plus
First Trimester
- GS
- Gestational sac first sign
- Yolk sac
- Embryo nutrition source
- FHR
- Fetal heart rate
- CRL
- Crown rump length
- NT
- Nuchal translucency
- MSS
- Mid sagittal plane
- Ectopic
- Extrauterine pregnancy
- Demise
- No cardiac activity
ALARA Safety
As Low As Reasonably Achievable
TI: thermal riskMI: mechanical riskDwell time minimalOutput lowest needed
UA vs MCA Doppler
Umbilical artery
- Placental resistance
- Absent end diastolic
- IUGR marker
MCA
- Fetal brain sparing
- Increased diastolic flow
- Anemia marker
Placenta vs fetal brain
Doppler + Physics
- Umbilical artery
- Fetal placental flow
- MCA
- Middle cerebral artery
- Uterine artery
- Maternal placental flow
- PI
- Pulsatility index
- RI
- Resistance index
- Spectral broadening
- Turbulent flow sign
- Reverberation
- Repeated echo artifact
- Shadowing
- Acoustic barrier artifact
Common Traps
AFI vs SDP
AFI sums quadrants ≠ SDP deepest pocket
TA vs TV early
TV for early OB ≠ TA for late anatomy
Previa vs low
Previa covers os ≠ Low lying near os
Simple vs complex
Simple thin anechoic ≠ Complex needs follow up
UA vs MCA flow
UA placental resistance ≠ MCA brain sparing
CRL vs BPD dating
CRL first trimester ≠ BPD second trimester
Last Minute
- 1.170 Q 3 hr scaled 555
- 2.37 percent second third trimester
- 3.24 percent protocols procedures
- 4.BPD HC AC FL biometry set
- 5.AFI sum four SDP deepest
- 6.TV early TA late anatomy
- 7.ALARA lowest practical exposure
- 8.CRL dates first trimester
- 9.60 day wait between retakes
- 10.SPI prerequisite before specialty
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