Fetal Growth Assessment Chapter 51 Flashcards
Between 38-42 weeks is called?
At term
Before 38 weeks is called?
Preterm
Later than 42 weeks is called?
post term
Decreased rate of fetal growth is known as what?
Intrauterine Growth Restriction (IUGR)
IUGR complicates less than _____% of pregnancies.
<10%
Fetal weight is at or below _____% for IUGR.
10%
IUGR posts a greater risk for what?
antepartum death, perinatal asphyxia, neonatal morbidity, later developmental problems, mortality increases six to ten fold
A fetus below the 10th percentile without reference to cause is considered what?
SGA (small for gestational age)
_____________ is a subset of the SGA as a result of a pathologic process.
IUGR
The causes for IUGR include….
- Maternal Disease States - DM (diabetes mellitus), SLE (Systemic Lupus Erythematosus), HTN
- Placental - Uteroplacental Insufficiency - UPI
- Fetal - genetic/chromosomal
Extensive, primary placental infarctions leads to ________.
UPI
Maternal and placental factors lead to what?
asymmetric IUGR
Fetal factors for IUGR are associated with what?
symmetric IUGR
Describe symmetric IUGR.
- Result of a long standing and/or severe maternal/placental cause.
- Chromosomal/genetic anomalies
- Infection (TORCH)
- Associated with first trimester insults
- Proportionally small in all physical parameters due to earlier impact
- May appear sonographically BEFORE 20 weeks
- Approximately 20% to 30% of all IUGR cases are symmetric
Describe asymmetric IUGR.
- Cause usually related to maternal disease states or later developing placental causes
- **last 8-10 weeks of pregnancy
- Disproportionate growth of head/abdomen
- Brain sparing - brain takes blood it needs at cost of abdomen growth
- **typically develops AFTER 24 weeks
- ***more common than symmetric
***The single most sensitive indicator of IUGR is?
AC -abdomen circumference
The most important ratio sonographically for IUGR is what?
HC/AC
Sonographic Parameters of IUGR include…
- Oligohydramnios
- Advanced placental grading (III between 34 to 36 weeks)
- Thin placenta
- Delayed appearance of epiphyseal sites
- Elevated RI’s cord Doppler - increased Doppler resistance/impedance
Biophysical Profile (BPP) assesses:
- fetal breathing
- fetal body movement
- fetal muscle tone
- AFI
- fetal heart rate changes (assessed with NST not US)
When does the CNS mature?
24 weeks & up
What is acute hypoxia?
decrease in breathing, movement, and heart rate activity
What is severe acute hypoxia?
absence of movement/tone
What is chronic hypoxia?
result of UPI; oligo & decreased movement is common
For BPP fetal breathing movements what must be seen?
- inward movement of chest wall with outward movement of abdominal wall
- 2 points if one episode of breathing lasts 30-60 sec within 30 minutes
- If absent no points are given
For BPP, what do you need to see for fetal gross movement?
- Three definite extremity or trunk movements in 30 minutes for 2 points
- Fewer than three scores zero points
For BPP, what do you need to see for AFI?
- 4 quadrants
- largest vertical pocket measured
- 1 pocket must measure at least 2 cm in two perpendicular planes
- exclude fetal limbs or cord
- normal is 5 to 22 cc based on age
For BPP fetal tone, what needs to be seen?
- extension and flexion of extremity or spine
- one episode in the 30 minutes score 2 points
- no episode scores 0 points
What are the two types of Umbilical Cord Doppler?
Quantitative - measure velocity
Qualitative - Characteristics of wave form
S/D of more than _______ in umbilical artery after 30 weeks is abnormal should never have absent or reversed end diastolic flow.
3.0
S/D of more than ______ in the maternal uterine artery is abnormal with diastolic notching after 22 weeks.
2.6
Fetus with IUGR- increase in vascular resistance/impedance reflects what?
Increased S/D ratio and RI
Macrosomia is classically defined as….
birth weight of 4000 g or greater or above 90th percentile for estimated gestational age
What two terms relate to macrosomic fetuses?
mechanical macrosomia and metabolic macrosomia.
What are the three types of mechanical macrosomia?
- Fetuses generally large
- Fetuses generally large but with especially large shoulders
- Fetuses with normal trunk but large head
Placental thickness greater than _____ is considered thick when measurement taken at right angles to its long axis
5 cm
