OB Diagnostic Imaging, procedures & Documentation Flashcards
Uses of the US in the first trimester
First Trimester: 1-12 weeks
- establish prescence or abscene of interuterine gestational sac & viability
- ecotpic pregnancy or other complications
- bleeding work up
- dating of pregnnacy: CRL: most accurate time to estimate date
use of US in second trimester pregnancy
Second Trimester: 13- 28 weeks
- due date confirmatino (can be off by +/- 2 weeks)
- Anatomy Scan at 18-22 weeks
- anomalites/amniocentesis
- multiples
- placental location
use of US in third trimester
Third Trimester: 29-40 weeks
- growth scan monitoring
- bleeding (abruption of placenta)
- BPP
- amniocentesis
US can also be used at any point in pregnancy to establish and evalulate growth scans for mothers with chronic disease which could impact fetus
First Trimesters US Scans
- development milestones
Determine presence of the Gestational Sac
- implantation in to the uterus
- careful not to confuse with corpus luteum cyst, which may have blood flow surrounding it too
Development
- 4 1/2 - 5 weeks: appearance of gestational sac
- 5-51/2 weeks: yolk sac apparent
- 6 weeks: embryo seen; fetal cardiac puslations
- 6.7-7 weeks: amniotic membrane appears
- 7-8 weeks: fetal spine appears
- 8 weeks: head & limbs distinct separation from torso
- 8-8 1/2 weeks: fetal motion can be felt
- 8-10 weeks: rhombencephalon
First Trimesters US Scans
- CRL and growth measurements
CRL: crown-rump-length
- the most accurate way to validate gestational age is to measure CRL and date gestation via US
measured
- from the crown of the head to the rump, or base of spine
generally
5 mm = 6 weeks
10 mm = 7 weeks
16mm = 8 weeks
22 mm = 8.8 weeks
First Trimesters US Scans
- type of US done
- US findings to indicate a viable preganancy
first trimester US must be done via TVUS since a pelvic will not reach deep enough
- any vaginal bleeding, cramping, pain or spotting warrents a TVUS in first trimester
Viable Pregnancy
- progressive increase in fetal HR from 1 US to next (like a week later)
- interuterine gestation confirmed iwth embryo and yolk-sace (CRL measured)
- evidence of growth via increasing CRL and increased fetal HR and evidence the cervix remains closed = viable pregnancy and location of the embryo in the uterus
First Trimesters US Scans
findings or suspicious of a pregnancy faillure
what would you find
Absent fetal cardiac activity
- if no HR by the time CRL is > 7mm = dx. of pregnancy failure
- if CRL is < 7 mm, suspcious but not a dx.
Absent Embryo
- if no embryo by the time the mean sac diamter is > 25mm = dx. of pregnancy failure
- if no embryo in two seperate US checks; even if found gestaional sac and yolk sac
Abnormal morphology of the gestaional sac, amnion or yolk sac
First Trimesters US Scans
Spontanous Abortion Signs
Spontaneous Abortion on US
- cramping & spotting = signs in first trimester
US evidence
- evidence of interuterine gestiation
- without HR
- movement of the gestational sac into the cervical canal & opening of cervix = indicates spontaneous abortion
First Trimesters US Scans
Subcorionic Hemorrhage on US
US First trimester: Subcorionic hemorrhage
- a collection of blood/fluid behind the placenta and where it attaches to the uterine wall (darker space behind the gestational sac)
can still have a viable and healthy pregnancy: just need to monitor more frequently
be suspicous for this if pt. presents with vaginal bleeding in first trimester
First Trimesters US Scans
Ectopic Pregnancy
Ectopic Pregnancy
assume abd. pain in any women of reproductive age is ecoptic until proven otherwise
presenting: cramping, pain, bleeding, etc. with + bHCG
US Findings
- the uterus will be EMPTY: nothing inside
- so you look to the adenxa: and you see the gestaional sac implanted in the adenax, ovary, etc. with fetal HR
- or you can look into the cervix: and see the gestational sac in there
First Trimesters US Scans
Gestational Trophoblastic Disease
US appearance
symptoms, dx and tx.
GTD: gestational Trophoblasic disease
- from the placenta: complete or partial hydatidiform moles can form
- benign or malignant
- hydatiform mole: empy egg or grape-like clusters or snowstorm pattern on US
- partial: part mole and part embryo, but often non-viable
- complete: all mole no viable pregnancy : higher risk of developing to a malignancy
Symptoms
- abnormal vaginal bleeding
- uterine size larger than date of pregnancy
- hyperemesis
- preeclampsia before 20 weeks
Dx.
- bHCG > 100,00 (marked elevation) persistanlty
- evidence of mole on US
First Trimesters US Scans
GTD
treatment for benign and malignantt
GTD
Benign
- complete or partial
- low risk: chemo
metastait
- chemo + radiation + surgery
- D&C to perserve fertility or TAH
serial bHCG monitoring: until baseline level achieved and then need to have contraception for 6-12 months after until total remission
First Trimesters US Scans
Reasons for vaginal bleeding
subchorionic hemorrage (MC)
implantation bleeding
threatened abortion
spontaneous abortion
all of these warrent a TVUS in the first trimester
Genetic/Aneuplodiy Screening in the First Trimester
First Trimester
Nuchal Translucency test: measures the nuchal space at the back of babies neck between 11-13 weeks “8-12wk scan”
Labs: get free BHcG + PAPP-A levels
if labs + and nuchal translucecny thickened ( >6mm) = high sensitivity for trisomy 21 but not 100%
a thickened nuchal tranlucency withOUT the labs = thick skeletal or cardiac abnormalities
Genetic/Aneuplodiy Screening : Second Trimester Screening
Quad Screen: four materal blood substances
Done between 15-22 weeks
these labs values + maternal age, weight, ethnicity, DM status and gestational age = estimate risk for trisomy 21 and 18
Values
MSAFP
BHcG
Estriol
Inhibin-A
Trisomy 18: all four levels will be decreased
Trisomy 21: BHcg + inhibin A elevated, MSAFP and estriol decreased
Trisomy 13: decreased bhcg and normal or elevated MSAFP
Screening results
- if women screens postive: there is a risk of these abnormalities, not 100%
- if this screen test is positive = move onto a detialed anatomy US
Postive Screening on second trimester Quad Screen
potential findings on teh anatomy screen which could clue you into….
Trisomy 21
Trisomny 21: anatomy scan findings
- brachecephaly
- broad nasal ridge
- low set ears
- oblique palpebral fissure
- simean creased
- cardiac (AV defects)
- duodenal atresia
- mental retadation
Postive Screening on second trimester Quad Screen
potential findings on teh anatomy screen which could clue you into….
Trisomy 18
Trisomy 18 (Edwards)
- pectus carinatum (outward)
- cardiac defects
- renal anomalies
- omphalocele
- overlapping fingers
- rockerbottom feet
- polyhydraminos
- small placenta
Postive Screening on second trimester Quad Screen
potential findings on teh anatomy screen which could clue you into….
Trisomy 13
Trisomy 13 (Patua’s Syndrome)
- holoproscencepahly (single brain lobe)
- clefting
- eye anomalies
- cardaic defects
- polydactaly
- rockerbottom feet
2nd Trimester US Scans
what scans are done
Anatomy Scan
lots of the 2nd trimester screens can be done in the 3rd as well
2nd trimester scans include
- anatomy scan
- due date confirmation
- anamolies/abnormalities
- placental location
- mutiples
Anatomy Scan
- done at the 18-22 week time frame
- measurements done here too (confirm due date)
Anatomy Scan
Fetal Head Scans: measurements where
Fetal Head Scan
- measurement at the level of the thalmus, not the cerebellum!!
what are you measureing
Biparietal Diameter (BPD)
- measure from teh otuside edge of one side to the inside edge of the other side
- also helps measures weight
Head Circumference
- assists with dating
Anatomy Scan
Spine
Heart
Spine
- obtained from lateral and trasnverse (overhead looking down) view
- assessment of neural tube and presence of neural tube defects: CNS malforamtions 2nd most common type
- NTD: see an outpuching of th nerual contents usually at the base of the spine
Heart
- looking for a four chamber heart
- assessing fetal HR
- hypoechoic spots on the heart: can be benign, but can also indicate genetic abnormality –> may want to offer screening if not done yet
Anatomy Scan
Abdominal
Cord
Abdominal Scan
- assess the presence of the organs location
- assess the presence of the cord
Cord
- 1 vein (to baby- oxygenated) to become ligamentu teres
- 2 arteries (away from baby to mom- deoxygenated)
- Wharton’s Jelly: connective tissue surrounding and cushioning vessles
- normal cord length: 50-60cm
- long cord: risk of cord injury wrapping
- short cord: risk of ruputre during delivery
Anatomy Scan
echogenic bowel
abd. circumeference
Abdominal Circumference
- measures the abd. to assess growth
Ecogenic Bowel
- area of brightness in the bowel on exam
- can be beign
- can also be a sign of CF
- can also be a sign of other genetic abnormalities
Anatomy Scan
limbs
Femur length
scan measurements in sum
Limbs
- count them all!
Femur Length
- measure from hip to knee
- helps measure growth
Anatomy Scan in Sum
- the scan can help estimate gestational age but its +/- 2weeks in teh second trimester
if the findings are not within the 2week period of the EDD = work up and figure out why baby is small/big,etc.
growth is monitored Q4weeks so repeat scans can be done in four weeks intervals
Fetal Size
- low/small
- healthy
- fetal macrosomia and IUGR
Estimations of the Baby can be made by OB
small: 5.5 lbs
normal : 8 lbs.
macro: 11 lbs.
IUGR: baby size < 5%tile of normal
macrosomia: baby size > 95%tile of normal
IUGR due to…
placental or cord abnormalities
- decrease perfusion, oxygen delivery, transport
- incorrect cord insertion, single artery
Materal Factors
- age, small statre, stress, pre-eclapsia, substance use, undernutrtion
- prior IGUR, HTN
- TORCH infections
Fetal Factors
- cong. HD
- diaprgmatic hernia
- Trisomy 21, 18 or 13
- turners
Fetal macrosomia
- maternal DM
- obesity in pregnancy
- genetics
- overdue baby
- male
- older maternal age
What is included in a Level 2 Anatomy Scan: needing further evaluation
Level 2: done if abnormalities found in the typicla anatomy scan or for those at an increased risk of abnormalities
Humerus length
Nasal Bone length
nuchal folds
cerebellar diameter
cisterna magna
cervical length
Additional Findings on the Anatomy Scan which can lead to a possible aneuplodiy suspicion
these can be benign if one is found, but when mutliple are, the risk of aneuplodiy increases
- echogenic focus in the heart
- chorid plexus cyst
- pyelectasis
- ecogeneic bowel
- short femus
- hypomineralization of the fifth digit on hand
Chorionic Villus Sampling
when is it done
what is it testing
how is it done
CVS: chorionic villus sampling
- an alternative to amniocentesis: can be done earlier than amnio.
- optional test: for those who want to know early, those with fmaily history,etc. : 99.9% accuracy!
when: can be done 10-12 weeks
- testing for aneuplodidy/genetic abnormalites only (or DNA analysis:CF,etc.)
- does NOT TEST for neural tube defects
How its done
- trascervical or transabdominal approach: depenidng on location of the placenta
- US guided: needle passed into the placenta to aspirtate for chorionic villi : analysis sent
pregnancy loss
- up to 1% each time
Amniocentesis
indications : when (2 times)
procedure
Amniocentesis
15-20 weeks : 2nd
- cytgenic analysis : genetic abnormalities
- APF for neural tube defects
3rd trimester
- can be done to diagnose intraamniotic infection
- documentation of fetal lung maturiaty
- therapeudic procedure for those with hydraminos: too much fluid
How its done
- needle inserted through abd. wall, into unterine cavity and fluid with the cells of fetus are removed
- US guided
- risk of loss is 1:200
Abnormalities on the Anatomy Scan : 2nd trimester
Anencephaly
Hydrocephalus
Occiptal Encephalocele
Anencephaly
- lack of brain development : parts of brain and skull
- saw often with Zika infection
Hydrocephalus
- increased/abnormal CSF buildup within the brain ventricles: increased pressure on the brain tissue
Occipital Encephalocele
- swelling of fluid over the occiptial bone midline
Abnormalities on the Anatomy Scan : 2nd trimester
gastroschisis
omphalocele
Gastroschisis
- abdominal organs through a hole int he abdominal wall: without a covering or sace to protect! they’re exposed
- baby will be fine; just need to know because we need to be prepared at delivery
- hole near the cord
Omphalocele
- like a gastrochisis but there is a fluid-filled thin naturally occuring sac thay is rarely opened or broken
Cervical measurements on US : second trimester
normal
cervical incompetence
Cervical Measurements
normal cervix: 4 cm (size of fist)
- should be closed from internal and external os
- measured from internal to external
Cervical Incompetence
- when the cervix begins to open or shorten in the absence of contractions, prematurly
- contrasted with premature labor: which is shortening on the cervix with contractions
- can be fully open from internal to external, or can be funnel shaped
How is this treated: Cerclage: a suture tie that keeps the cervix closed during pregnantc
cannoy cerclage: if there is contractions or infection
- removed ususally at 32 weeks incase contractions and labor begin
What is the Placenta
Placenta
- materno-fetal interface: critical for proper fetal development
- typically attaches to fetal wall at during first trimester = bleeding possibility
- cord connects here to supply nourishment and oxygen to the baby
What is it
- fetal in origin: two layers (the chorion and the amnion)
- contains trophoblasts: which release bHCG: allow crpus lutem to persist
Placental Implantation : Placenta previa
types
Implantation
- within the first trimester
- location can be foudn via US
as the fetus grows, the belly will expand upwards: the upward: thus the placenta will “grow” upwards
Placenta previa: abnormal placental local- located close to or over the cerivcal os
- this is a bleed risk!
Placenta Previa Types
complete: the placenta covers the cervical os c section needed if within 2 cm
partial: partly covering the cervical os
marginal: sitting next to the edge of the os
low-lying: within 3 cm of the cerivcal os
Risk Factors for Placenta Previa
symptoms (hallmark 1 )
Risk Factors
- multipary: 7+
- advanced maternal age
- prior C section or surgery
- smoking
- prior abortion
Symptoms
painless vaginal bleeding
need to have limited instrumentaion, no intercourse, exercise, etc. = c section will be needed
Placenta Accreta
Placeenta Accreta
- when the placenta grows into the muscular layer of the uterus (into the myometrium or beyond)
- may not be known until placenta cannoy be delivered
Signs on US
- see areas called lacunae which are diagnositic of an adherant placenta
- indicate a sticky unterus wall and possible failure of the placenta to not dis-adheare during palcental devliery
Risk Factors
- prior D&C or instrumentation/surgery
Effects & what to do
- decreased the bleeding asap
- may need to do a TAH to stop the bleeding
Reasons for Bleeding for 2nd/3rd trimester
placenta previa
placental abruption (complete pull off the uterine wall)
cervical incompetence
preterm labor
Placenta Preveia v Abruption
Previa
- painless
- variable amount of bleeding: but there will be some
- visable on US
Aburption
- painfuL!!!!!
- maynot have bleeding if it is concealed within the placenta
- often have risk factors which make them known to be high risk
- may not be able to be identified on US
What is Fetal Monitoring
when and why is it done
Fetal Monitoring
- to look for signs of fetal distress or hypoxia
- usually for babies in distress, those at risk or those
- ensureing proper nutrients and oxygen getting to the fetus
- for high risk pt. (later done during delivery)
How its done
- external trasnducer attached to mom’s abdomen
- one will detect moms contractions = trochometer
- one will detect babys HR
Non-Stress Test
when can it be done
Non-Stress Test
- a test done to monitor fetal HR in the absence of contractions
- if contractions = stress test
When
- done starting at 28-32 weeks
- not done before 28 weeks because its difficult to see accelerations before this time
Non-Stress Test
tocometer
fetal HR & varibailities
Tocometer: reads moms uterus: determines if there are contarctions
- contractions will appear like mountains on the bottomes strip
- every red line distance = 1 minute
Fetal HR: the top strip
baseline: determine the baseline BPM (should be 110-160) without the acels
Want to see variability on the stripe
- absent variability = little to no squiggles = bad
- mild variability: not great, want to do something (1-5 beats) prokvoking to see the acels to ensure baby is ok
- moderated varibaility= what we want to see (6-25 beats above/below)
- marked variability: above 25 up or down from baseline: bad
Fetal HR on the stress test
accels
decels
accels
- accelerations: we want to see these!
- indicate baby is ok
- we want to see 15 beats above for at least 15 seconds (at least 2 in 20 minutes)
Decels
Early Decels: typically due to head compression : see the HR of fetus dropping with the contraction: they are in line with each other
- seeing early decels with accels i sok
Variable Decels
- random sshort dips in teh heart rate without relation to the contractions
- this is due to Cord Compression!!
- see these in short period with an accel is ok
Late Decels = BAD SIGN
- these are decels which begin with the contraction but end AFTER the contraction, they end later hence, late decels
- they are due to fetal/palcenta insuffiency
- may be a sign needing to deliver
Fetal Bradycardia and Tachycardia
Bradycardia
- continous baseline below 115
- this is a LATE finding of hypoxia
- THIS INDICATES A NEED TO C SECTION IMMEDIATELY
Tachycardia
- contuous baseline above 160
- this is an early finding of hypoxia
- can be due to tinteruterine use of terbutaline
Sinusoidal pattern
- BAD SIGN
- immediate delivery
Biophysical Profile
BPP: a test that can be done if needed after doing a fetal non-stress test
- this can be done as the next step if needed: not all babies will get this
What does it include: a 30 minute test
- fetal HR assessment: the non-stress test
- fetal breathing movements
- gross body movements (flextion, extension, etc.)
- fetal tone (hypotonia or normal tonia)
- qualitative amniotic fluid volume
Normal = score of > 8/10
score of 6 = wait and repeat
score of < 4= bad sign
Aminotic Fluid
how is its amoutn calculated (for the BPP)
Aminotic Fluid
- protection & lung develpoment
- important indicator of fetal well being
- fetus swallows this, pees it back out
Amniotic Fluid Index
- amount that is “normal” depends on gestational age
- divide abdomen into 4 quadrants
- measure teh fluid while the woman is laying flat on her back: find larger pocket in each quadrant
- between 5th-95th percentile isnormal amount
can test amniotinc fluid, drain and see if theres too much etc.
Fetal Blood Sampling
Fetal Blood Sampling
- percutaneous umbilical blood sampling (PUBS) aka cordocentesis
- done under US guidance
- an option for chromosomal or metabolis anyalysis of the fetus
good to detect
- Rh sensitization (monitor the Rh factor in baby)
- neontal alloimmune throbocytopenia
higher risk for
- featl death 2% risk every time you do it & this needs to preformed often
Determining Presentation
Leopold’s Maneuver
Leopolds maeuver
- determination of fetal postioning inthe uterus
- vertex: head down: want this for devliery
- leopolds: feeing the cephalic prominence (hard top of the head) for it at the pubic symphisis
what occupies fundus: whats at the top
location of small parts: feet and hands
Presenting part: whats at the pubic symphsis
wheres the head: if its not here…
Breech Positioning
Breech = position in which babies head is not down
Frank Breech: cannonball with legs strigh up
complete breech: cannonball with legs crossed
incomplete breech: one leg up and dwon cannonball
footling: one foot first
Dx. Breech
- US to find heda
- pevlic exam
- leopold manuever
OB Documentation Pearls
Gestaional Age : alwasy document GA in note
- include GA in week and how it was determined: FDLMP, 1st trimester growth scan, 2nd trimester?
Nagele’s rule
- FDLMP - 3months + 7 days (plus 1 year)
Gs & Ps
- G = gravidity (currently pregnent)
- Ps: FPAL
- full term
- preterm
- abortions
- living
Bishop Scoring
APGAR
Bishop Scoring
- a labor note uses this: to assess readiness for/initiation of labor
- determines the likelihood of a vaginal birth to be successful
- score of > 8 = successful vaginal birth
Bischop looks at
- dilation
- effacement
- station
- consistency
- positon
APGAR
- newborn infant at 1 and 5minutes
- score 0-10 with 7+ meaning good and < 4- resusitate
