Abnormal Fetal Growth Flashcards
Standard Routine Measurements
Biparietal diameter (BPD) Head circumference (HC) Abdomen circumference (AC) Femur length (FL)
Head Measurements
BPD HC Cephalic index (CI) Transverse Cerebellum Binocular
Criteria for BPD
CSP (Cavum septum pellucidum) & thalamus No cerebellum Hemispheres symmetrical Ultrasound beam 90 degrees to midline echo Calipers placed at widest part of skull
IUGR vs SGA
DO NOT confuse IUGR with term small for gestational age (SGA).
SGA describes fetus with weight below 10th percentile without reference to cause.
Fetal growth restriction describes subset of SGA fetuses with weight below 10th percentile as result of pathologic process from variety of maternal, fetal, placental disorders.
Symmetric IUGR
All measurements small (BPD, HC, AC, FL) genetic disorders (e.g., trisomy 18), fetal infections (e.g., rubella and cytomegalovirus), congenital malformations, and a variety of syndromes (e.g., Cornelia de Lange)
Asymmetric IUGR
Head measurements correlate with age (BPD, HC)
Other measurements small (AC, FL)
relative nutritional and oxygen deprivation
Prenatal effects of IUGR
Increased mortality Decrease in umbilical vein volume Decreased cardiac output Increased cerebral circulation Heart failure
Postnatal effects of IUGR
Increased Short and long term morbidity Learning disabilities Behavioral problems Reduced cognitive function High blood pressure Diabetes Acquired heart disease
Maternal risk factors with IUGR
Low socioeconomic status/ poor maternal nutrition
Coexisting maternal disease, infection or genetic disorder incl:
Collagen vascular disease ( i.e. systemic lupus erythematosus)
Chronic and severe renal cardiovascular or respiratory diseases
Hypertension and preeclampsia
Diabetes Antiphospholipid antibody syndrome
Inflammatory bowel disease
Lung disease
Sickle cell anemia
Maternal drug use/teratogenic exposure
Hx of child of unexplained low birth wt.
Hx of IUGR pregnancy
Hx. Preterm birth
Fetal risk factors with IUGR
Aneuploidy Congenital infections ( CMV, varicella zoster) Genetic syndromes Congenital anomalies Monochorionic twins Twin to twin transfusion Higher order multiples
Placental risk factors of IUGR
Placental abruption Placenta previa Marginal or velamentous umbilical cord insertion Placental neoplasms Circumvillate placenta Advanced placental grade Placental mosaicism
weight-based theories
Low birth weight Varies with gestational age IUGR Borderline at 25% Diagnosed at 10%
weight-based theories requirements
Gestational age Estimated fetal weight (EFW) calculation BPD, AC (Shepard) HC, AC, FL (Hadlock) Gestational age (weeks), HC, AC (multiplied by 2), FL (Sabbagha) Third trimester measurements
echogenic bowel can indicate
Pathology
Doppler fetus IUGR
redistribution of blood within the fetus and placenta
what factors affect the fetal spectral waveform
- patient position
- fetal/maternal breathing
- fetal cardiac abnormalities
- maternal ingestion of pharmacologic agents
umbilical artery
normal-low resistance above the baseline
Abnormal-high resistance with no or little end-diastolic flow, possible flow reversal
Cerebral blood flow
Normal pregnancy there is continuous forward flow in the fetal MCA
MCA is the main lateral branch of the circle of Willis
High resistance circulation results in a high Doppler reading in a normal fetus (this is opposite of the case in other fetal vessels)
With fetal growth restriction, there is a marked decrease in cerebral resistance - Results in a low Doppler ratio
what occurs with growth restriction
Blood will be shunted towards the brain, which will change the MCA from being high resistant to low resistant and will have a low Doppler ratio
what will occur in hypoxia
Blood will be shunted towards the braian, the heart and the adrenal gland
with compensation, during diastolic
will see increased blood flow
Uterine Artery Doppler
Uterine artery travels along the lateral aspect of the uterus from the level of the cervix
Most readily identifiable location for sampling the uterine artery with u/s is at the level of the cervix
In non pregnant women & early pregnancy ut artery has a notch at the beginning of the diastolic phase of the cardiac cycle
In the 2nd / 3rd trimester the presence of a notch or persistently elevated ratios – pregnancy may suffer inadequate nutrition or O2- this can lead to pre eclampsia and IUGR
Macrosomic
Weight greater than 4200-4500 grams regardless of the GA
Large for Gestational Age
LGA refers to a fetus or infant who is larger than expected for the age and gender. It can also mean an infant with a birth weight above the 90th percentile.
large for gestational age complications
A baby that is large for gestational age has a higher risk of birth injury.
There is also a risk of complications of low blood sugar after delivery (if the LGA is due to maternal diabetes).
Common causes of large for Gestational age
Gestational diabetes
Prolonged pregnancy
Erythroblastosis fetalis
Some non chromosomal genetic syndromes (e.g., Beckwith-Weidemann synrome)
what is APGAR
Apgar is a quick test performed on a baby at 1 and 5 minutes after birth.
The 1-minute score determines how well the baby tolerated the birthing process.
The 5-minute score tells the doctor how well the baby is doing outside the mother’s womb.
In rare cases, the test will be done 10 minutes after birth.
what are the five components of APGAR score
Breathing effort Heart rate Muscle tone Reflexes Skin color
Each category is scored with 0, 1, or 2, depending on the observed condition.
Biophysical components
Nonstress test (NST) Fetal Breathing Movements Tone Qualitative amniotic fluid volume
fetal movement
2 points if three or more discrete body or limb movements within 30 minutes of observation
fetal tone
2 points if one or more episodes of extension of a fetal extremity or fetal spine with return to flexion
fetal breathing
2 points if one or more episodes of rhythmic breathing movements of ≥30 seconds within a 30 minute observation period
Amniotic fluid
2 points if a single pocket of fluid is present measuring ≥2 cm in 2 perpendicular planes
Sonographic BPP score
Max of 8!!
Score of less than 4
Indicates fetal compromise
Maximum biophysical profile score
10 (includes stress test and sonographic things)
Nonstress testing results
2 points if reactive, defined as at least 2 episodes of FHR accelerations of at least 15 bpm and at least 15 seconds duration from onset to return associated with fetal movement within a 30 (different sources give different times for the test 20-40 minutes) minute observation period
Amniotic fluid index
Four quadrant measurement of fluid
Perpendicular measurement
Fluid pocket free of cord / fetal parts
Sum of all reported
Amniotic fluid volume
largest vertical pocket
Borderline AFI
<5cm = Oligohydramnios >25cm = Polyhydramnios 8-22 = normal
Fetal causes of oligohydramnios
Fetal asphyxial states / IUGR Premature rupture of fetal membranes Developmental anomalies of the genitourinary system Chromosomal abnormalities Congenital syndromes Intrauterine fetal demise
Maternal cause of oligohydramnios
Uteroplacental insufficiency
Drugs
Placental causes of oligohydramnios
Placental abruption
Twin - twin transfusion
causes of polyhydramnios
- Increased Production of Amniotic Fluid.
2. Decreased Elimination of Amniotic Fluid.
Single deepest pocket measurement
Measure the dimensions of the largest vertical pocket of amniotic fluid which is free of umbilical cord and fetal parts.
Pocket of fluid:
Less than 2 cm Oligohydramnios
Greater than 8 cm Polyhydramnios
