PU First Trimester Ultrasound and Dating 2

Question 1

What finding on first-trimester ultrasound is most suggestive of a failed pregnancy (missed abortion)?

Accepted Answer

CRL ≥7 mm with no cardiac activity on transvaginal scan

Answer

Per ACOG/SRU criteria, a CRL of 7 mm or greater with no visible cardiac activity on transvaginal ultrasound is diagnostic of embryonic demise.

Question 2

What is the normal fetal heart rate range in the first trimester?

Accepted Answer

100–170 bpm

Answer

Normal first-trimester fetal heart rates range from approximately 100 to 170 beats per minute, with rates below 100 bpm at 6–8 weeks associated with poor prognosis.

Question 3

What is the mean sac diameter (MSD)?

Accepted Answer

The average of three perpendicular measurements of the gestational sac

Answer

MSD is calculated by averaging three perpendicular internal measurements (length, width, height) of the gestational sac and is used to assess early pregnancy development.

Question 4

The nuchal translucency (NT) measurement is performed at what gestational age range?

Accepted Answer

11–14 weeks (CRL 45–84 mm)

Answer

NT measurement is performed between 11+0 and 13+6 weeks gestation, when the CRL is between 45 and 84 mm, for first-trimester Down syndrome screening.

Question 5

What does an increased nuchal translucency (NT ≥3.5 mm) indicate?

Accepted Answer

Increased risk of chromosomal abnormalities, cardiac defects, and genetic syndromes

Answer

An NT of 3.5 mm or greater is associated with significantly increased risk of trisomies (21, 18, 13), Turner syndrome, cardiac defects, and various genetic syndromes.

PU - Pregnancy Ultrasound Certification Practice Test

PU - Pregnancy Ultrasound Certification Practice Test

PU First Trimester Ultrasound and Dating 2