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Flashcards in Fetal Age & Measurements Deck (64)
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1

Sonographic measurements of the fetus provide info about...

1. fetal age
2. EFW
3. diagnose growth disturbances

2

This is the true measure of age, the number of days since conception.

conceptual age

3

This is the number of days since the first day of the last menstrual period.

menstrual age

4

Accurate knowledge of gestational age is important...

Telling normal from abnormal and timing of ...
1. CVS
2. amnio
3. elective induction
4. cesarean

5

Dating by LMP may be inaccurate because of...

1. variability of cycle length
2. faulty memory
3. oral contraceptives
4. bleeding during early pregnancy

6

Determining gestational age from fundal height may be affected by...

1. uterine fibroids
2. multiple pregnancy
3. maternal body habitus

7

From 5-6 weeks, there are two methods for assigning gestational age. They are?

1. MSD
2. contents of the sac

8

This is the average internal diamter of the sac.

MSD

9

The sac is _mm at 5 weeks and _mm at 6 weeks.

2, 10

10

You should only use the MSD for dating if..

you don't see an embyro.

11

If the difference between the MSD and the CRL is 5 mm or less there's a high risk of...

spontaneous abortion.

12

The heartbeat should always be seen from __ weeks onward.

6.3

13

The term 'embryo' applies until the __ week.

10

14

CRL correlates closely with GA until around the __ week.

13

15

What are the main measurements in the 2nd and 3rd trimesters?

1. BPD
2. HC
3. AC
4. FL

16

If the AC is too short, look for signs of...

IUGR.

17

If the FL is too short, look for signs of...

skeletal dysplasia.

18

What are the three head measurements?

1. BPD
2. OFD
3. HC

19

BPD measures from the ___ edge of the near side of the cranium to the ___ edge of the far side of the cranium.

outer, inner

20

What anatomic landmarks do you need to measure the BPD?

1. symmetrically postioned thalami
2. cavum septum pellucidum
3. falx

21

Sonographically, this refers to the relationship between the fetal cranial sagittal suture and the central portion of the u/s beam.

angle of asynclitism

22

For an exact BPD, the angle of asynclitism should be...

90 degrees to the cranial sag suture

23

This is the length of the outer perimeter of the cranium, made at the same level as the BPD.

HC

24

T/F? HC should include scalp echoes when using the ellipse method.

FALSE, should not

25

This is the measure of the long axis of the fetal head, at the same level as the BPD.

OFP

26

The OFP should be measured from the ___ edge to the ___ edge.

outer, outer

27

In this condition, the AP length of the fetal head is shortened.

brachycephaly

28

In this condition, the AP length of the fetal head is lengthened.

dolicocephaly

29

This is obtained by measuring the widest and longest dimension of the fetal skull.

cephalic index (CI)

30

This should be used to evaluate the validity of the BPD, if the head is an unusual shape.

CI