Antenatal fetal assessment and IUGR Flashcards
what are the goals of fetal surveillance
prevent fetal death
prevent neonatal morbidity
what are some ways to assess fetal wellbeing in the office
s/sx of disorders of hx–> gestational HTN, general maternal health
fetal movement–at least 6 movements within 2 hours, starting after 26 weeks
BP
maternal weight gain
symphysis-fundal height (SFH)
fetal HR with doptone
indications for antenatal fetal assessment/surveillance
pre-existing medical conditions–> pre-existing diabetes, hypertension, cardiac disease, lupus
pregnancy related–> multiple gestation, oligohydramnios, postdates, PPROM, 2nd/3rd trimester bleeding (?abruption or placenta previa)
previous fetal demise
what does oligohydramnios make us worry about?
amniotic fluid is a measure of fetus fluid status–> i.e low amniotic fluid means baby urine output is down–> sign of poor placental perfusion
define IUGR
estimated fetal weight is less than 10th percentile
abdominal circumference is less than 10th percentile
includes many normal fetuses–> 25-75% are constitutionally small
excludes fetuses that stopped growing
clinical definition postnatally is birth weight below the 10th percentile
how does SGA differ from IUGR
IUGR is pathological, SGA can be normal and just happens to be small
symmetrical IUGR definition
all measurements are small for GA
likely due to: congenital infection chromosomal abnormality congenital malformation maternal drug ingestion alcohol abuse genetic syndromes constitutional
asymmetrical IUGR
this is likely due to deficiency in nutrients
results in large head (because spares nutrients for brain) whereas rest of body is small
mostly a placental functioning issue
why do we care about IUGR
second most common cause of perinatal mortality
fetal death increases x8 between the 10th and 3rd percentiles
fetal death is x20 when birth weight is less than 3rd percentile
30% of infants who die of SIDS were IUGR
more susceptible to asphyxia
higher rates of meconium aspiration
hypoglycemia due to decreased glycogen reserves
hypocalcemia–> second to hyperparathyroid
hypothermia
polycythemia–x3-4
hypercoagulability
hyperbilirubinemia–due to polycythemia
thrombocytopenia
what usually causes variable decelerations
cord compressions–not too worrying
what usually causes late decelerations
hypoxia–worry–consider making sure delivers quickyl
what usually causes decelerations timed with contractions
head compression/vagal response from fetus–not too worrying
how do you interpret a BPP score
any score 4 or less–> DELIVER BABY
how much of the placenta has been affected (placental arteries obliterated) when you get reversed end-diastolic flow
70%
measuring end diastolic flow (biophysical profile–BPP) with doppler is the one test we have that actually can have an impact on fetal outcomes
how often do you check fetal growth when monitoring for IUGR
every 2 weeks