Module 3 : Maternal Testing Flashcards
1
Q
what are the ultrasound exams done for obstetrics
A
- dating first trimester
- 1st trimester scan
- 2nd trimester detailed
- FAS and BPP
2
Q
what test is done fro early pregnancy testing
A
- serum beta guman chorionic gonadotropin
3
Q
what is bHCG produced by
A
- trophoblast
4
Q
what is bHCG and indicator of and how is it tested
A
- early indicator of pregnancy
- blood test or urine test
5
Q
how do bHCG levels change
A
- double every 2 days
6
Q
at what week does bHCG levels plateau
A
- 8 weeks
7
Q
what three things could a decreased bHCG suggest
A
- missed abortion/ fetal demise
- ectopic pregnancy
- wrong dates
8
Q
what two things could an increased in bHCG indicate
A
- trophoblastic disease (molar pregnancy)
- multiple pregnancies
9
Q
what is a NIPT
A
- non invasive prenatal testing
- maternal blood test taken at 10 weeks LMP
10
Q
what does a NIPT test for
A
- cell free DNA in maternal plasma
+ placental DNA in maternal blood
11
Q
is the NIPT test accurate and what does it screen for
A
- 100% detection rate
- T21 T13 T18
12
Q
in what 5 situations is a NIPT less effective
A
- obese patients
- pregnant with multiples
- pregnant via donor egg
- less than 10 weeks pregnant
- taking blood thinners
13
Q
what is the purpose of prenatal testing
A
- offers early information about a baby’s risk for certain chromosomal conditions
14
Q
what is prenatal testing a combination of
A
- nuchal translucency
- first trimester blood tests
+ bHCG
+ PAPP-A
15
Q
what is the nuchal translucency test
A
- measurement of the collection of fluid under the skin at the back of the baby’s neck
16
Q
what does in increase in nuchal size correspond to
A
- increased risk of chromosomal and other abnormalities
17
Q
when is the nuchal measured
A
- only between 11 weeks (CRL 45mm) and 13 weeks (CRL 84mm)
18
Q
what is the max AP measurement of the nuchal translucency
A
< 3.5mm
19
Q
what does an increase in bHCG between 11-14 weeks possibly indicate
A
- trisomy 21
20
Q
what does a decrease in bHCG between 11-14 weeks possibly indicate
A
- trisomy 18 and 13
21
Q
what produces the pregnancy associated plasma protein A and what is it
A
- placental syncytiotrophoblast and deciduas
- glycoprotein
22
Q
how does PAPP-A change with pregnancy
A
- rapid increase in levels during first trimester
23
Q
what dose a decreased PAPP-A between 11-14 weeks possibly indicate
A
- trisomy 21 and 18
24
Q
what is the detection rate of the NT and biochemical tests in the first trimester
A
- 85% detection rate
25
what constitutes a positive first trimester screen test
- less than a 1:300 ratio
26
what three factors are used together to screen for abnormalities
- maternal age
- nuchal translucency
- maternal biochemistry
27
what other sonographic test/factor increases detection rate to 95%
- presence of a nasal bone
28
what is a hypo plastic nasal bone
- fetal NB appears smaller by varying degrees
| - less tha 2.5mm
29
what is an absent nasal bone
- NB not visible at the 11-14 weeks scan
30
what is the 2nd trimester screen (triple/quad screen)
- maternal serum testing between 15 and 20 weeks
31
what is the triple screen
- assess 3 different elements (AFP, bHCG, uE3)
32
what is the quad screen
- asses 4 different elements found in the maternal blood
| - AFP, bHCG, uE3, Inhibin A
33
where is MS AFP produced
- fetal liver
- yolk sac
- GI tract
- Kidneys
- placenta
34
how does MS AFP levels change
- levels will rise from about 14-20 weeks
35
how does AFP enter maternal circulation
- crosses the placental plate into maternal circulation
36
what is the most common cause for abnormal level of MS AFP
- wrong dates for gestational age
37
in what women can MS AFP be increased
- athletic women
| - diabetic moms
38
what placental condition can cause increased AFP
- placental abruptions
39
what does a decrease in AFP possibly indicate
- trisomy 21 and 18
40
what does and increase in AFP possibly indicate
- open neural tube defect
- abdominal wall defect
- GI obstruction
- RH sensitivity
- placental abnormality
- fetal death
41
in what four things will bHCG be increased in the quad screen
- multiples
- molar pregnancy
- wrong dates
- T21
42
what 2 things will bHCG by decreased in quad screen
- fetal demise
| - trisomy 18
43
what is uE3 (estriol)
- measured only in pregnancy
| - produced by placenta
44
when is uE3 found how do levels change
- found as early as 9th week of pregnancy
| - levels continue to rise throughout pregnancy
45
what are 3 things does a decrease in uE3 possibly indicate
- T21, 18
- pregnancy loss
- adrenal insufficiency
46
what is inhibin A
- hormone produced by placenta
47
what are increased levels of inhibin A associated with
- trisomy 21
48
is there any change in inhibin A levels with trisomy 18
- no
49
what are the quad screen levels with trisomy 21
- AFP decrease
- bHCG increase
- uE3 decrease
- Inhibin A increase
50
what are the quad screen levels with trisomy 18
- AFP decrease
- bHCG decrease
- uE3 decrease
- inhibin A doesn't change
51
is trisomy 13 detected with triple or quad screen
- nope
52
what are the two types of chorionic villi sampling
- transcervical CVS
| - transabdominal CVS
53
when is a transcervical CVS performed
- 11-12.5 weeks
54
how is a transcervical CVS performed
- catheter inserted through cervix to chorion frondosum
| - with a negative pressure syringe moving catheter back and forth to capture chorionic villi cells
55
when is a transabdominal CVS performed
can be done beyond 12.5 weeks
56
how is a transabdominal CVS performed
- needle through abdomen to chorion frondosum
| - performed when placenta cannot be accessed by transcervical approach
57
what determines the type of CVS performed
- depends on where the chorion frondosum lies (placenta)
58
which test obtains more DNA and and gets result faster amnio or CVS
- CVS
59
what is the risk with CVS
- possible spontaneous abortion
60
what is an amniocentesis
- amniotic fluid is aspirated from the amniotic sac via a needle through the maternal abdomen
61
what are the risks with amniocentesis
- bleeding
- pre mature rupture of membranes
- pre term labour
- club feet
- spontaneous abortion
62
when is club feet a risk from amniocentesis
- when performed earlier than 16wks
63
what is the scanning protocol for amniocentesis
- number of fetuses and position
- amniotic fluid volume
- placenta location
- gestational age
- limited anatomical survey
- record M Mode heart rate before and after procedure
64
what are the 4 types of amniocentesis
- cytogenic amnio = chromosomes, most common
- optical density determination = RH sensitized
- L/S amnio = fetal lung maturity
- therapeutic = for poly
65
when is a cytogenic amnio performed
- between 11x to term
66
how is a twin amnio performed
- after amnio aspirated from first gestational sac indigo carmine injected then second baby is sampled if it comes out wth dye then not in the right spot
67
what does a ODD amnio test for
- measure bilirubin level in RH sensitized pregnancy
68
what is the L/S ratio amnio test for
- lecithin and sphingomyelin are fairly equal up to 33 weeks
- beyond this lecithin increases where S remains constant
- if ratio is grater than 2:1 lungs are matured
69
why is a therapeutic amnio performed
- done for poly
- done when the mother is not able to to tolerate pressure fo large uterus pressing on abdominal contents causing shortness of breath
70
what is PUBS
- percutaneous umbilical blood sampling
| - CORDOCENTESIS
71
how is a PUBS performed
- needle into umbilical cord about 2-3cm from insertion into placenta
- take sample from vein rather than artery
72
what are the indications for a PUBS procedure
- chromosomal analysis within 72 hours
- fetal blood gas sampling in IUGR fetuses
- fetal infection s
- FETAL ANEMIA IN RH SENSITIZATION
- FETAL BLOOD TRANSFUSIONS VIA PUBS
- trat fetal arrhythmias with medication via PUBS
73
what are three risks from PUBS
- bleeding from puncture site
- infection
- rupture of membranes
74
what is a FISH Test
- fluorescence in situ hybridization
| - looks for how many copies are present for a specific chromosome
75
what two things is not required with FISH
- does not require all the steps needed as in cytogenic aryotyping
- does not give info on the structure of that chromosome
76
what can a FISH be performed on
- fetal blood
- amniotic fluid
- CVS
