ICL 15.8: Fetal Disorders

Question 1

which drug causes baldness?

Answer 1

methimazole

causes aplasia cutis

Question 2

how many days post conception does it take for the pregnancy test to be positive?

Answer 2

day 9 or 10

positive from hCG form the syncitiotrophoblasts

Question 3

patient is 31 days pregnant, what is her post-conceptual age?

Answer 3

17 days

Question 4

which drug is associated with fetal discoloration of teeth?

Answer 4

tetracycline

Question 5

which structure carries oxygenated blood from the placenta to the fetus?

Answer 5

umbilical vein

gives rise to the ductus venosus

Question 6

what category of aneuploidy does this represent: 45,XO

Answer 6

Turner’s syndrome

monosomy

Question 7

all or non insults occur during this time period?

Answer 7

first two weeks after conception

the blastocyst after 2 weeks has implanted into the endometrium so anything that damages the inner cell mass is going to be lethal

Question 8

division before which post conception day results in a dichorionic/diamniotic twin gestation?

Answer 8

day 3 or 4

blastocyst must divide before implantation to get 2 totally different gestational sacs!

once implantation occurs, trophoblasts attach to endometrium and any division that occurs in the blastocyst that occurs will only result in one chorion and one amniotic sac/placenta any time after day 6

Question 9

when is implantation?

Answer 9

day 6 is when blastocyst implants

Question 10

if the blastocyst divides after day 6 but before day 9, what kind of twin gestation will you have?

Answer 10

one chorion but two amiotic sacs

this is because you’re after implantation so there can only be one placenta but it’s before the amniotic sac forms (day 9) so you’ll get two sacs with one placenta

Question 11

if the blastocyst divides after day 9 and before day 12 what kind of twin gestation will you have?

Answer 11

conjoined twins

monochorionic and monoamniotic so two babies in one sac with one placenta

this is because the amnion can’t divide after day 9

Question 12

if there is division after day 12, what kind of twin gestation will you have?

Answer 12

conjoined twins with one amniotic sac and one chorion

Question 13

what tissue gives rise to the placenta?

Answer 13

trophoblasts from the blastocyst

Question 14

what connects the fetal pulmonary artery and aorta?

Answer 14

ductus arteriosus

Question 15

how do you maintain a PDA?

Answer 15

prostaglandins

indomethacin closes it

Question 16

the highest resistance to blood flow is found in which fetal organ?

Answer 16

the fetal lungs

highest resistance is in the pulmonary artery specifically in utero

Question 17

which drug is associated with Ebsteins anomaly?

Answer 17

lithium

Question 18

what is the cause of no fetal limb formation?

Answer 18

thalidomide

Question 19

what is the most common cause of pregnancy loss before 12 weeks?

Answer 19

aneuploidy = abnormal number of chromosomes

more specifically trisomy and even more specifically it’s trisomy 16 because it’s completely incompatible with life

Question 20

what is the most common cause of oocyte aneuploidy in women over 35?

Answer 20

meiotic nondisjunction

oogonia appear at 20 weeks gestation and the longer we’re alive, the more likely the chromosomes are to misbehave

Question 21

what is the zygosity of monochorioc mono amniotic twins?

Answer 21

monozygotic

two fetuses that came from one zygote that developed into a blastocyst and implanted then divided