Abnormal Growth Flashcards
How is GA determined?
LMP
mean gestational sac
CRL
BPD, FL, AC, HC
Small for GA babies have a birth weigh below the _____ __________.
10th percentile
What causes SGA?
genetics
IUGR
*most SGA babies are small bc of fetal growth problems that occur during pregnancy
IUGR:
occurs when fetus doesn’t receive the proper necessary nutrients and oxygen needed
can occur anytime in pregnancy
early onset is due to chromosomal abnormalities, maternal dx or severe placental problems
What are some maternal factors that can contribute to SGA or IUGR?
high BP chronic kidney dx adv diabetes heart/respiratory dx malnutrition/anemia infection substance use cigs
What are uterus/placental factors that contribute to SGA or IUGR?
dec blood flow in uterus + placenta
placental abruption
placental previa
infection in tissues around fetus
What are fetal factors that contribute to SGA or IUGR?
multiple gestations
infection
birth defects
chromosomal abnormalities
Perinatal mortality rate is _____ higher than infants born with appropriate weight for GA; the risk of asphyxia is _____ higher.
8x
7x
Babies w/ SGA or IUGR may have problems at birth including:
dec oxygen levels low Apgar scores meconium aspiration hypoglycemia difficulty maintaining normal body temp polycythemia
What are most cases of IUGR caused by?
placental insufficiency
either primary or secondary (hypertension, collagen vascular dx, poor nutrition or substance abuse)
IUGR can either be __________ or ___________
asymmetrical or symmetrical
IUGR is normally used to refer to small fetuses with a higher risk of?
utero deterioration, stillbirth and overall poorer perinatal outcome
Symmetrical SGAs-
all measurements (HC, length, weight) are reduced. Usually caused in early pregnancy (chromosomal abnormalities, rubella)
Asymmetrical SGAs-
only have a weight reduction, with a normal sized head circumference and body length
Insults that appear in the 3rd trimester (hypertension)
The most common cause of early onset (symmetrical) IUGR is what? What’s the second most common?
chromosomal abnormality (aneuploidy)
second is fetal infection
Which type of IUGR is more common?
asymmetrical (2/3rds)
Why is the head size of fetus with asymmetrical IUGR normal?
blood flow is directed towards the fetal brain at the expense of the other organ systems
What is the single best parameter for diagnosing asymmetrical IUGR?
AC measurement
if AC growth is less than 1cm in 14days this indicates IUGR (after appts repeated 2wk intervals)
What are non-specific findings of IUGR?
oligohydramnios placental senescence (grade 3 placenta before 36wks) delayed sonographic appearance of the distal femoral ossification center
Macrosomia refers to fetuses:
above the 90th percentile for GA
most often defined as fetal weight >4000g
most complications occur with fetuses weighing more than >4500g
What’s the most common risk factor for macrosomia?
maternal diabetes
What are factors of macrosomia?
diabetes* previous delivery of a large infant maternal obesity tall mother excess weight gain during pregnancy multiparity adv maternal age >35 post term delivery
Large fetuses have a higher incidence of ?
perinatal morbidity and mortality
birth trauma- shoulder dystocia, fractures, facial + brachial plexus palsies, birth asphyxia, prolonged pregnancy
