Lesson 4A (Part 1) Flashcards Preview

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Flashcards in Lesson 4A (Part 1) Deck (32)
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1
Q

When does the first US assessment take place?

A

0-13 weeks

2
Q

What is the first US assessmnet also known as?

A

Dating US

- date of when baby was conceived

3
Q

What gets assessed in the dating US? (3)

A
  1. Gastational sac
    - presence (confirm IUP)
    - number
    - size (gestational age)
  2. Embryo
    - size (gestational age)
    - cardiac activity
  3. Maternal structures
    - uterus, ovaries, cervix, adnexa, fibroids, cysts, ectopic pregnancies and molar pregnancies
4
Q

Molar pregnancy

A

Abnormal pregnancy

5
Q

What is the patient preparation for the first trimester assessment? (3)

A
  1. No fasting
  2. Full bladder
    - for transabdominal
  3. Empty bladder
    - for transvaginal
6
Q

What kind of questions do you ask for patient history in the first trimester assessment? (7)

A
  1. When was your LMP?
  2. Have you had a positive pregnancy test?
  3. Any gravidity, parity or abortus?
  4. Is the patient having pain or bleeding?
  5. Is the patient on any medication?
  6. Has the patient had a previous C-section?
  7. Any complications with previous pregnancies?
7
Q

Which type of US do you get a more accurate reading?

A

Transvaginal

8
Q

What embryological structures slowly become visible During early development? (in order to appearance) (4)

A
  1. Decidual reaction
  2. Gestational Sac
  3. Yolk Sac
  4. Embryo
9
Q

What day does implantation occur on?

A

Day 20-23

  • the conceptus is 0.1 mm at the end of implantation
  • not visible, even on TV
10
Q

What is the first reliable sign of an intrauterine pregnancy?

A

The gestational sac

11
Q

What cavity is the gestational sac located in?

A

The chorionic cavity

12
Q

When is the gestational sac visible?

A
  1. 5-5 weeks

- once the mean sac diameter reaches 2-3 mm

13
Q

Where is the gestational seen within?

A

The decidua

- intradecidual sac sign (IDSS)

14
Q

What must you distinguish the gestational sac from? (2)

A
  1. Pseudogestational sac

2. Decidual cysts

15
Q

Pseudogestational sac

A

Small amount of fluid within the endometrial cavity

- between the endometrial layers

16
Q

Decidual cysts

A

Small cysts that can form within the decidual reaction

17
Q

What will the true gestation sac be like? (5)

A
  1. Round –> oval
  2. Eccentric
  3. Directly adjacent to the endometrial lining
  4. Will develop a yolk sac and embryo
  5. Will develop a double decidual sac sign
18
Q

DDSS

A

Double decidual sac sign

19
Q

How is DDSS seen?

A

2 concentric rings surrounding the gestational sac

20
Q

What does the DDSS consist of? (2)

A
  1. Decidua parietalis
    - outer
  2. Decidua capsularis
    - inner
21
Q

What can DDSS differentiate between? (2)

A
  1. Abembryonic pole
  2. Embryonic pole
  • site of future placental development
22
Q

MSD

A

Mean sac diameter

23
Q

Mean sac diameter

A

Is the common mode of measurement

- averages 3 perpendicular planes

24
Q

What is the formula for MSD?

A

MSD = (L + W + H)/3

25
Q

How do you measure the gestational sac?

A

From inner to inner walls

- only the fluid/anechoic part

26
Q

What is the mean sac diameter used to calculate?

A

The gestational age

27
Q

How much does the gestational sac per day?

A

1mm/day

  • if MSD is about 2 mm → GA 4 to 4.5 weeks
  • if MSD is about 5 mm → GA is 5 weeks
28
Q

When does the yolk sac appear?

A

5.5 weeks

29
Q

What happens at week 6?

A

Embryo appears adjacent to the yolk sac

30
Q

When is the yolk sac present?

A

When the is MSD = 8 mm (TV)

31
Q

When is the embryo present?

A

When the is MSD = 16 mm (TV)

32
Q

What happens if the gestational sac is larger than 8mm without a yolk sac or larger than 16 mm without an embryo?

A

Then it may be a sign of early pregnancy failure