ObGyn Flashcards
What is the earliest sign of pregnancy seen on transvaginal US?
The earliest sign of pregnancy seen with transvaginal ultrasound is the intradecidual sign, an anechoic sac without a distinct chorionic ring. This may be seen as early as four weeks of gestation. However, a thin walled sac within the uterus is not definitive evidence of an intrauterine pregnancy!
What is the definitive sonographic evidence of an IUP?
Definitive sonographic evidence of an intrauterine pregnancy is established when a gestational sac containing a yolk sac is identified in two planes within the endometrium. This occurs around the fifth week of gestation.
Starting with a transabdominal probe in a transverse setting what structures will you see?
The transverse plane just above the pubic symphysis directed down towards the uterus. Using a curvilinear probe
In the transabdominal longnitudinal position what structures will you see?
The transabdominal ultrasound employs ideally a 3.5 MHz curvilinear probe and begins just above the pubic symphysis in a longitudinal axis. It is best performed when the patient has a full bladder, which not only provides a good window for viewing underlying structures, but also displaces overlying bowel
What shows up at the 6th week of gestation?
At six weeks gestation, the heart tubes of the embryo fuse and both a fetal heart beat and a fetal pole can be identified
What mode is used to obtain fetal heart rate?
Using M mode (motion) we are able to visualize the movement of the fetal heart over time.
When the gestational sac reaches this __ diameter you should see a yolk sac.
Signs suggestive of abnormal embryonic development include a gestational sac greater than 10 mm in diameter without a visible yolk sac
When the gestational sac reaches this diameter, one should see a fetal pole?
A gestational sac greater than 18 mm in diameter without a fetal pole is suggestive of abnormal embryonic development.
