Chapter 7 Fetal Complications of Pregnancy

Question 1

2 most common teratogens that cause SGA are

Answer 1

alcohol and cigarettes.

Question 2

intrauterine infections that lead to SGA:

Answer 2

cytomegalovirus (CMV) and rubella. , accounts to 10-15% of all sGA babies.

Question 3

maternal risk factors for sga:

Answer 3

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.

Question 4

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.

Answer 4

ultrasound to evaluate fetal growth is common even without abnormal fundal height measurements.

Question 5

if sga is suspected, accuracy of pregnancy’s dating should be verified.

Answer 5

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.

Question 6

another test to differentiate iugr fetus is doppler investigation of the

Answer 6

umbilical artery.

Question 7

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 __

Answer 7

intrauterine fetal demise.

Question 8

pts with hx of placental insufficiency, preeclampsia, collagen vascular disorders, or vascular disease are often reated with

Answer 8

low dose aspirin.

Question 9

pts with prior placental thrombosis, thrombophilias, or antiphospholipid antibody syndrome have been treated with

Answer 9

heparin and corticosteroids.

Question 10

sga fetuses should have expedited delivery

Answer 10

false. there is no indication to expedite delivery in SGA fetuses who have been consistently small throughout the pregnancy.

Question 11

large gestational age and fetal macrosomia is having an efw greater than

Answer 11

90th percentile

Question 12

american college of obstricians and gynecologists use a weight greater than ___ as macrosomia

Answer 12

4500. may clinicians also use birth weights of greater than 4,000-4200g.

Question 13

macrosomic fetuses have a higher risk of shoulder dystocia and birth trauma with resultant ___ injuries with vaginal deliveries

Answer 13

brachial plexs.

Question 14

mothers with lga or macrosomic fetuses are increased risk for

Answer 14

1. c/s
2. perineal trauma
3. postpartum hemorrhage.
   women with lga have higher rate of c/s due to failure to progress in labor.

Question 15

most classically associated risk factor for fetal macrosomia is

Answer 15

preexisting or gestational diabetes mellitus. bmi >30 or weight greater than 90kg is also correlated with fetal macrosomia.

Question 16

fundal height screen has a relatively poor sensitivity and specificity for fetal growth disorders.

Answer 16

true.

Question 17

oligohydramnios is associated with __ increase in perinatal mortality

Answer 17

40 fold.

Question 18

without the amniotic fluid to cushion it, umbilical cord is more susceptible to compression thus leading to

Answer 18

fetal asphyxiation.

Question 19

etiology of oligohydramnios

Answer 19

can be thought of as either decreased production or increased withdrawal.

Question 20

amniotic fluid is produced where?

Answer 20

by the fetal kidneys and lumgs. it can be resorbed by the placenta, swallowed by the fetus, or leaked out into the vagina.

Question 21

what causes oligo?

Answer 21

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.

Question 22

diagnosis of oligo

Answer 22

afi <5. some center use the deepest vertical pocket of amniotic fluid less than 2cm as diagnostic for oligohydramnios.

Question 23

polyhydramnios defined by AFI greater than

Answer 23

20-25.

Question 24

fetal structural and chromosomal abnormalities are more common in polyhydramnios. such as

Answer 24

1. maternal diabetes and malformations such as:
2. neural tube defects NTD.
3. obstruction of the fetal alimentary canal
4. hydrops.

Question 25

polyhydramnios is not as ominous a sign as oligohydramnios

Answer 25

true but, it is associated with congenital anomalies.

Question 26

polyhydramnios is more common in pregnancies complicated by

Answer 26

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.

Question 27

increased risk of cord prolapse with polyhydramnios. thus, ROM should be performed in a controlled setting.

Answer 27

VE should be performed to verify fetal presentation and r/o cord prolapse.

Question 28

if woman is RH-, fetus is RH+, woman may be sensitized to the RH antigen and develop antibodies. how?

Answer 28

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.

Question 29

define fetal hydrops

Answer 29

accumulation of fluid in extracellular space in at least 2 body parts.

Question 30

if pt is RH- but has a negative antibody screen, the goal during pregnancy is to keep her from becoming sensitized.

Answer 30

true

Question 31

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

Answer 31

rhogam and anti D immunoglobulin RhIgG. an antibody screen is performed at the initial visit to detect prior sensitization.

Question 32

standard dose of rhogam 0.3g of Rh IgG will eradicate __ ml of fetal rbcs

Answer 32

15mls. .

Question 33

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.

Answer 33

kleihauer-betke test.

Question 34

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,

Answer 34

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.

Question 35

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

Answer 35

true

Question 36

when there is no explanation for fetal demise, it is usually attributed to

Answer 36

cord accident.

Question 37

a retained iufd >3-4 weeks can lead to

Answer 37

hypofibrinogenemia, secondary to release of thromboplastic substanes from the decomposing fetus. full-blown disseminated intravascular coagulation (DIC) can result.

Question 38

monoCHORIONIC

Answer 38

ONE placenta