Lesson 4A (Part 1) Flashcards
When does the first US assessment take place?
0-13 weeks
What is the first US assessmnet also known as?
Dating US
- date of when baby was conceived
What gets assessed in the dating US? (3)
- Gastational sac
- presence (confirm IUP)
- number
- size (gestational age) - Embryo
- size (gestational age)
- cardiac activity - Maternal structures
- uterus, ovaries, cervix, adnexa, fibroids, cysts, ectopic pregnancies and molar pregnancies
Molar pregnancy
Abnormal pregnancy
What is the patient preparation for the first trimester assessment? (3)
- No fasting
- Full bladder
- for transabdominal - Empty bladder
- for transvaginal
What kind of questions do you ask for patient history in the first trimester assessment? (7)
- When was your LMP?
- Have you had a positive pregnancy test?
- Any gravidity, parity or abortus?
- Is the patient having pain or bleeding?
- Is the patient on any medication?
- Has the patient had a previous C-section?
- Any complications with previous pregnancies?
Which type of US do you get a more accurate reading?
Transvaginal
What embryological structures slowly become visible During early development? (in order to appearance) (4)
- Decidual reaction
- Gestational Sac
- Yolk Sac
- Embryo
What day does implantation occur on?
Day 20-23
- the conceptus is 0.1 mm at the end of implantation
- not visible, even on TV
What is the first reliable sign of an intrauterine pregnancy?
The gestational sac
What cavity is the gestational sac located in?
The chorionic cavity
When is the gestational sac visible?
- 5-5 weeks
- once the mean sac diameter reaches 2-3 mm
Where is the gestational seen within?
The decidua
- intradecidual sac sign (IDSS)
What must you distinguish the gestational sac from? (2)
- Pseudogestational sac
2. Decidual cysts
Pseudogestational sac
Small amount of fluid within the endometrial cavity
- between the endometrial layers
Decidual cysts
Small cysts that can form within the decidual reaction
What will the true gestation sac be like? (5)
- Round –> oval
- Eccentric
- Directly adjacent to the endometrial lining
- Will develop a yolk sac and embryo
- Will develop a double decidual sac sign
DDSS
Double decidual sac sign
How is DDSS seen?
2 concentric rings surrounding the gestational sac
What does the DDSS consist of? (2)
- Decidua parietalis
- outer - Decidua capsularis
- inner
What can DDSS differentiate between? (2)
- Abembryonic pole
- Embryonic pole
- site of future placental development
MSD
Mean sac diameter
Mean sac diameter
Is the common mode of measurement
- averages 3 perpendicular planes
What is the formula for MSD?
MSD = (L + W + H)/3
