Transcript ObUsConcepts

Jan Charmaine Almonte-Saret
M.D., FPOGS, FPSUOG
equal or less than 13 weeks
-
-
Indications and advantages:
confirmation of intrauterine pregnancy/ early
pregnancy failure
best estimation of G.A.
Evaluation of vaginal bleeding
Evaluation of ectopic pregnancy
Confirmation of multiple pregnancy
Evaluation of pelvic, ovarian or uterine
pathology
GUIDELINES FOR DATING PREGNANCY
STAGE OF
GESTATIODEVELOPMENT NAL AGE
(WEEKS)
Gestational sac
5 weeks
Gestational sac
with yolk sac
Gestational sac
with yolk sac &
embryo
LEVEL OF BHCG
5.5 weeks
1,000-2,000
mIU/L
7,200 mIU/L
6 weeks
10,800 mIU/L
NUCHAL TRANSLUCENCY
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11 to 14 wks
=/> 3 mm
Screening for fetal chromosomal
abnormalities
screening for trisomy 21
NON-BIOMETRIC PARAMETERS
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Uncertain of menstrual dates
Measurement disparity in late trimester
Narrow down error in estimation gestational age
TRANSCEREBELLAR DIAMETER (TCD)
- Numerically equivalent to the number of weeks of
gestation
NON-BIOMETRIC PARAMETERS
COLONIC GRADE
•
>/= 16 weeks- grade 1, anechoic lumen
•
at 26 weeks & more- grade 2- lumen appears
more echoic
•
>/= 36 weeks- grade 3, lumen becomes brigther
SECOND & THIRD TRIMESTER
DISTAL FEMORAL EPIPHYSES (DFE)
•
at least 32-33 weeks
PROXIMAL TIBIAL EPIPHYSES (PTE)
•
Seen at 35 weeks
PROXIMAL HUMERAL EPIPHYSES
(PHE)
•
•
at 38 weeks or more
reliable predictor of term gestation
SIGNIFICANCE OF THE RATIOS

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Cephalic Index (CI)BPD/OFD X 100 (74-83)
> 83- brachycephaly –may suggest a genetic
abnormality
< 74 – dolichocephaly – seen with
oilgohydramnios & breech presentation
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FL/AC RATIO –evaluating skeletal dysplasia
- < 0.16 suggestive of a lethal type
HC/ AC RATIO- determines growth lag; high ratio –
implies fetal malnutrition/IUGR
FL/BPD RATIO- can be used as one of the screening
parameters for Down’s syndrome ( short femur &
normal BPD= high ratio)
-
Gold standard for antepartum fetal surveillance
WHEN TO REQUEST?
-Antepartum testing started @ 26-28 weeks if with
maternal complications
-@ 32-34 weeks for high risk patients
-
HOW FREQUENT?
Repeated weekly
Most authors suggest 2x/week BPS &NST for:
1. IDDM
2. GDM with previous stillborn
3. IUGR
4. Post term pregnancy
5. Preeclampsia
What are the signs of fetal hypoxia?
Chronic Hypoxia (compensated)
1. Oligohydramnios
2. Asymmetric (head-sparing) IUGR
Acute Hypoxia (non-compensated)
1. Abnormal fetal heart rate changes
 Non-reactive NST
 (+) CST
MODIFIED BPS
-uses 2 parameters, NST ( acute marker of fetal compromise) &
AFV (chronic marker)
Nueral Control of Fetal Biophysical
Activities
BIOPHYSICAL
PARAMETER
CNS CENTER
GESTATIONAL
AGE
Fetal tone
Cortex- subcortical
area
7.5-8.5 wks
Fetal movement
Cortex- nuclei
9 wks
Fetal breathing
Ventral surface of 4th
ventricle
20-21 wks
Fetal Heart
Reactivity
Medulla & Posterior
Hypothalamus
24-26 wks
Note:
In pregnancy complicated by IUGR, DOPPLER
VELOCIMETRY studies will enhance the
perfomance of BPS – changes in Doppler
findings occur 4 days prior to the deterioration
of BPS
A sonologic procedure to assess maternal and
fetal
vascular
resistance
(vasoconstricted/vasodilated)  the state of
fetal perfusion.
To whom should we request it for?
1. Diabetes
2. Maternal HPN
3. Autoimmune Diseases - SLE, APAS,
Collagen vascular disease
4. Anemia
5. Post term Pregnancy
6. Unexplained Recurrent Pregnancy losses
7. Discordant multifetal pregnancy
8. IUGR
UTERINE ARTERY
WHAT ARE THE ABNORMAL RESULTS?

Presence of notching

Increase indices (SD, RI, PI)
AND IT’S SIGNIFICANCE?
Increase in the utero-placental resistance
(vasoconstriction)
Higher chance of pregnancy complications
UMBILICAL ARTERY
vasoconstriction
increase intraplacental resistance
elevated indices
decreased fetal perfusion
fetal hypoxia then IUGR
ABSENT END DIASTOLIC FLOW (AEDF)
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highest risk to develop adverse perinatal outcome
the mean duration from AEDF to onset of fetal
distress is 6-8 days
REVERSED END DIASTOLIC FLOW (REDF)
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most extreme form of intraplacental vascular
resistance
diagnosis to distress interval 4.2 +/- 1.4 days with
perinatal moratality rate of 50%
MIDDLE CEREBRAL ARTERY
What is an abnormal result?
DECREASED INDICES- brain sparing reflex
Remember:
fetal hypoxia
induces compensatory reflex
preferential blood flow to the brain (MCA
dilatation=decreased indices) while
vasoconstriction in the less vital organs
NOTE:
A sudden restoration of MCA indices to normal or
higher or increasing indices from a serial decreasing
pattern is omninous= failure of the fetal cerebral
vessels to vasodilate = acute fetal brain injury
Patients who are at high risk to develop abnormally
adherent placenta includes:
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Multiparity
Hx of previous CS
Hx of previous curettage
Placenta previa implanted anteriorly in the LUS
1.
Unusually intense blood flow within the
sonolucent space beneath the placenta
2.
Hypervascularization within the placenta and non
placental tissues
3.
Turbulence of flow in areas where placentas
appears to have lost parenchyma and within
placenta lacunae
Should be done routinely in a 20-24 weeks
gestation
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Lowers perinatal mortality
Lethal malformations-corrected early or
appropriate timing of delivery to allow surgical
intervention; if not amenable to surgery, early
counseling
ADVANTAGES OF TVS OVER TAS
1.
Patient discomfort
2.
Clearer images
3.
Eliciting pain and tenderness
4.
Earlier diagnosis of pelvic pathology
5.
Good for obese patients and with abdominal scars
DISADVANTAGES OF TVS OVER TAS
1.
2.
3.
Discomfort & pain to pxs with intact hymen and
postmenopausal
Large pelvic masses
Refusal of the procedure
MENSTRUAL ENDOMETRIUM
CYCLE
OVARY
Menstrual
phase
Early
proliferative
Thin echogenic line Developing
follicles (5-10)
Isoechoic
Leading follicles
Late
proliferative
Secretory
phase
Trilaminar
Thick &
Hyperechoic
Dominant
follicles (18-24)
Corpus luteum
Evaluates tubal patency
primary investigative tool for infertility
When it is performed?
First part of the menstrual cycle (Day 10-12)
advantage of eliminating the risk of X-ray
exposure & hypersensitivity to radiographic
contrast media
Evaluation of endometrial pathology
Evaluation of ovaries for follicular growth
Evaluation of pelvic organs & structures for
lessions and masses