OB Exam 1 Flashcards
(78 cards)
How can a sonographer determine what position the baby is in?
Find the head and spine
When is determining a due date the most important?
In the first trimester
Why should color not be used on a 1st trimester ultrasound?
color adds more energy to rapidly changing tissue, creating an added risk
ALARA
As Low As Reasonably Achievable
What do you use to estimate gestational age?
LMP and Naegele’s Rule
Naegele’s Rule
LMP - 3 months + 7 days
Sonographic establishment of gestational age
40 weeks, 3 trimesters
What is the 1st trimester?
- embryological development
- first 13 weeks
What is the 2nd trimester?
- fetal anatomy development
- 13-26 weeks
What is the 3rd trimester?
- fetal growth
- 27-40 weeks
Most babies are about the same size until when?
20-24 weeks
Following fetal growth (no longer gestational age)
- subsequent exam: age should be based on 1st ultrasound EDC/EDD
- look at symmetry of anatomical growth
What to look for in the 1st trimester?
- dating
- pain
- bleeding
- aneuploidy screening
- pelvic mass
What could pain in the 1st trimester be associated with?
ectopic
What could bleeding in the 1st trimester be associated with?
- spontaneous abortion
- check FHT (fetal heart tone)
What is an aneuploidy screening?
- test for abnormal # of chromosomes
- nuchal translucency (space in back of neck)
- maternal biochemical (mom’s blood lab values)
- possible chorionic villus sampling (early placenta biopsy) or amniocentesis (sampling amniotic fluid)
What to look for in the second trimester?
- fetal anatomy survey
- aneuploidy screening
- fetal growth
- pain/bleeding
Genetic markers in an aneuploidy screening
- multiple genetic markers
- hard markers = strong association
- soft markers = some association
What could pain/bleeding be associated with in the second trimester?
extrafetal structures and maternal adnexae
What to look for in the third trimester?
- fetal growth
- fetal well-being
- cervical stability
- presentation
- pain/bleeding
Fetal well-being assessment in the third trimester
- look for fetal abnormalities; anatomy/growth
- maternal conditions
- fetal environment
What could pain/bleeding be associated with in the third trimester?
placenta abruption
Basic protocol of a first trimester exam
- a pelvic exam w/ crown-rump length & heart rate
- evaluate uterus, endo, ovaries, cervix, & adnexae