Chapter 7 Fetal Complications of Pregnancy Flashcards
2 most common teratogens that cause SGA are
alcohol and cigarettes.
intrauterine infections that lead to SGA:
cytomegalovirus (CMV) and rubella. , accounts to 10-15% of all sGA babies.
maternal risk factors for sga:
hypertension, anemia, chronic renal disease, antiphospholipid antibody syndrome, systemic lupus erythematosus (SLE), and severe malnutrition. severe diabetes with extensive vascular disease may also lead to IUGR.
use of fundal height as screening tool for either sGA or LGA is quite poor with sensitivities well below 50%, and positive predictive vaules below 50% as well.
ultrasound to evaluate fetal growth is common even without abnormal fundal height measurements.
if sga is suspected, accuracy of pregnancy’s dating should be verified.
any infant at risk for iugr or being sga is followed with serial ultrasound scans for growth every 2-3 weeks. a fetus with decreased growth potential will usually start off small and stay small, whereas one with iugr will progressively fall off the growth curve.
another test to differentiate iugr fetus is doppler investigation of the
umbilical artery.
normal flow through umbilical artery is higher during systole and decreases only 50%-80% during diastole. the flow during diastole should never be absent or reversed, which is particularly concerning and is associated with a high risk of __
intrauterine fetal demise.
pts with hx of placental insufficiency, preeclampsia, collagen vascular disorders, or vascular disease are often reated with
low dose aspirin.
pts with prior placental thrombosis, thrombophilias, or antiphospholipid antibody syndrome have been treated with
heparin and corticosteroids.
sga fetuses should have expedited delivery
false. there is no indication to expedite delivery in SGA fetuses who have been consistently small throughout the pregnancy.
large gestational age and fetal macrosomia is having an efw greater than
90th percentile
american college of obstricians and gynecologists use a weight greater than ___ as macrosomia
- may clinicians also use birth weights of greater than 4,000-4200g.
macrosomic fetuses have a higher risk of shoulder dystocia and birth trauma with resultant ___ injuries with vaginal deliveries
brachial plexs.
mothers with lga or macrosomic fetuses are increased risk for
- c/s
- perineal trauma
- postpartum hemorrhage.
women with lga have higher rate of c/s due to failure to progress in labor.
most classically associated risk factor for fetal macrosomia is
preexisting or gestational diabetes mellitus. bmi >30 or weight greater than 90kg is also correlated with fetal macrosomia.
fundal height screen has a relatively poor sensitivity and specificity for fetal growth disorders.
true.
oligohydramnios is associated with __ increase in perinatal mortality
40 fold.
without the amniotic fluid to cushion it, umbilical cord is more susceptible to compression thus leading to
fetal asphyxiation.
etiology of oligohydramnios
can be thought of as either decreased production or increased withdrawal.
amniotic fluid is produced where?
by the fetal kidneys and lumgs. it can be resorbed by the placenta, swallowed by the fetus, or leaked out into the vagina.
what causes oligo?
uteroplacental insufficiency. because the fetus likely does not have the nutrients or blood volume to maintain an adequate glomerular filtration rate. UPI is commonly associated with growth restricted infants.
diagnosis of oligo
afi <5. some center use the deepest vertical pocket of amniotic fluid less than 2cm as diagnostic for oligohydramnios.
polyhydramnios defined by AFI greater than
20-25.
fetal structural and chromosomal abnormalities are more common in polyhydramnios. such as
- maternal diabetes and malformations such as:
- neural tube defects NTD.
- obstruction of the fetal alimentary canal
- hydrops.
polyhydramnios is not as ominous a sign as oligohydramnios
true but, it is associated with congenital anomalies.
polyhydramnios is more common in pregnancies complicated by
diabetes, hydrops, and multiple gestation. obstruction of the GI tract may cause fetus unable to swallow amniotic fluid, leading to polyhydramnios. hydrops associated with high output cardiac failure. monozygotic multiple gestations can lead to twin to twin transfusion syndrome with polyhydramnios around one fetus and oligohydramnios around the other.
increased risk of cord prolapse with polyhydramnios. thus, ROM should be performed in a controlled setting.
VE should be performed to verify fetal presentation and r/o cord prolapse.
if woman is RH-, fetus is RH+, woman may be sensitized to the RH antigen and develop antibodies. how?
igG antibodies cross the placenta and cause hemolysis of fetal RBCs. in sensitized pts with RH + fetuses, antibodies cross the placenta and cause hemolysis leading to disastrous coplications in the fetus.
define fetal hydrops
accumulation of fluid in extracellular space in at least 2 body parts.
if pt is RH- but has a negative antibody screen, the goal during pregnancy is to keep her from becoming sensitized.
true
any time during pregnnacy if there is a possibility that a pt may be exposed to fetal blood, such as during amnio, miscarriage, vaginal bleeding, abruption, and delivery, she should begiven
rhogam and anti D immunoglobulin RhIgG. an antibody screen is performed at the initial visit to detect prior sensitization.
standard dose of rhogam 0.3g of Rh IgG will eradicate __ ml of fetal rbcs
15mls. .
in the setting of placental abruption or any antepartum bleeding ______ should tested for amount of fetal rbcs in the maternal circulation. if the amount o fetal rbcs is more than can be eliminated by a single rhogam dose, additional dosages an be given.
kleihauer-betke test.
if + antibody for RH- comes back, titer is checked as well. antibody titers of 1:16 and greater have been associated with fetal hydrops. if paternity is not in question,
blodtype can be performed on the FOB to determine whether fetus is at risk. throughout pregnancy, antibody titer is followed approximately every 4 weeks.. as long as it is <1:16, pregnancy can be managed expectantly.
at the 1st amniocentesis, fetal cells collected and analyzed for the Rh antigen to determine fetal Rh status. if -, pregnancy can be followed expectantly. however, if fetus is Rh+, fetal amenia is screened
true
when there is no explanation for fetal demise, it is usually attributed to
cord accident.
a retained iufd >3-4 weeks can lead to
hypofibrinogenemia, secondary to release of thromboplastic substanes from the decomposing fetus. full-blown disseminated intravascular coagulation (DIC) can result.
monoCHORIONIC
ONE placenta
