Ultrasound in Obstetrics Flashcards
(48 cards)
What is an Obstetric Ultrasound
Obstetric Ultrasound is the use of ultrasound scans in pregnancy
What is the name of the equipment used in ultrasund scans
Real-Time Scanners
Explain briefly how Real time scanners work
Sound waves are emitted from a transducer that is placed in contact with the maternal abdomen
It is moved around to look at any particular content of the uterus
What is a requirement for an ultrasound in early pregnancy
full bladder
What are the 7 main uses of ultrasonography
- Diagnosis and confirmation of early pregnancy
- Vaginal bleed during early pregnancy
- Determination of gestational age and fetal size
- Detection of abnormalities
- Polyhydramnios and Oligohydramnios
- Multiple Pregnancies
- Placental localization
The gestational sac can be visualized as early as which week
4 1/2 weeks
When can the yolksac be observed
5 weeks
When can the embryo be observed and measured
5 1/2 weeks
What is the normal heart rate at 6 weeks
90-110 bpm
What is the normal heart rate at 9 weeks
140-170 bpm
How is the diagnosis of a missed abortion usually made
by serial ultrasound scans demonstrating lack of gestational development
if ultrasound demonstrates a 7mm embryo but cannot demonstrate a clearcut heartbeat, a missed abortion may be diagnosed
What are the five standard biometric parameters to estimate gestational age and /or foetal weight
Crown Rump Length (CRL) Biparietal Diameter (BPD) Head Circumference Abdominal Circumference (AC) Femur Legth (FL)
When should the Crown-Rump measurement be made
Between 7-13 weeks
Which biometric parameter to estimate gestational age and/or fetal weight is best studied and highly reproducible
Biparietal Diameter
BPD can be used to predit gestational age when measured between which weeks of pregnancy
14-20
BPD can be used to predict gestational age within what range
+/-7 days
What is the plane that both the BPD and Head Circumference are measured on
Measured on a plane of section that intersect the thalami and the third ventricle
Which is the single most important measurement in late pregnancy
Abdominal Circumference
Why is abdominal circumference the most important measurement in late pregnancy
serial measurements useful in monitoring growth
What is the “Femur Length” used to measure
Measures the longest bone in the body and reflects the longitudinal growth of the fetus
The femur increases from what length at 14 weeks to what length at term
1.5cm at 14 weeks to 7.8 cm at term
What is nuchal translucency?
It is a term used to describe sonographic appearance of a collection of fluid under the skin behind the fetal neck at 11-13 weeks of pregnancy
What abnormalities can Nuchal Transluceny detect?
Down’s Syndrome
Trisomy 21
Structural abnormalities in the foetus can be detected by which week of pregnancy
Week 20
