Tải bản đầy đủ

Ultrasound Evaluation During the First Trimester of Pregnancy

Ultrasound
Evaluation During the First
Trimester of Pregnancy
W Bruce Clark, M.D.




Vaginal ultrasound is usually superior to
abdominal scanning


Resolution is superior because
The transducer tip is closer to the pregnancy
 This allows a higher frequency transducer




The exception being nuchal translucency



More freedom of movement on the anterior
abdominal wall


Gestational Sac





First ultrasound sign of pregnancy
At 4 weeks 1 day to 4 weeks 2 days 2-3 mm
At 5 weeks 5mm, can be seen abdominally
Beware of the pseudo sac


5 week sac


Yolk Sac


Transvaginal




Appears at 5 to 5.5
weeks
Mean Sac Diameter
(MSD) 5mm to 8mm



Transabdominal


Appears at 7 weeks




Mean Sac Diameter
(MSD) 20mm

Maximal Diameter 5-6mm at Crown Rump Length (CRL)
of 30-45mm
Visualization of Yolk Sac confirms Gestational Sac rather than a
Pseudo Sac


6 week with yolk sac


Cardiac Activity


Transvaginal




Earliest seen at 34
days, CRL 1.6 mm
Should be seen at 6.06.5 weeks, CRL 4 to
5mm, or MSD 13 to
18mm



Transabdominal


Should be seen at 8
weeks, MSD 25mm


First Trimester


Gestational Age


Best predicted by the Crown Rump
Measurement


Signs of First Trimester Pregnancy
Failure







Sac with no embryo
Embryo ≥ 4 mm with no FH
Small sac size
First trimester bradycardia
Yolk sac too big, irregular, or calcified
Slow embryo growth


Ultrasound Findings of an Abnormal
Sac



MSD >8 mm without yolk sac
MSD > 16 mm without embryo


Using HCG values to evaluate
abnormalities of pregnancy




Blood 5µ/ ml ~ 3 or 4 days
Urine 50µ/ ml ~ 10 days
Ultrasound 1,000-1,500µ/ml ~18 – 20
days
(gestational sac)


First trimester fetal abnormalities



Fetal Abnormalities
Nuchal translucency








ULTRASOUND IN PRIVATE
PRACTICE
W. Bruce Clark, M.D.


First Trimester


Gestational Age


Crown Rump Measurement



First Trimester Ultrasound


Twins/Multiples



Zygosity
Membrane Status



Gestational Age



Likelihood of Spontaneous Abortion



Signs of First Trimester Pregnancy
Failure







Sac with no embryo
Embryo ≥ 4 mm with no FH
Small sac size
First trimester bradycardia
Yolk sac too big, irregular, or calcified
Slow embryo growth



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Tải bản đầy đủ ngay

×