Genetic Screening

Question 1

When does genetic screening start

Answer 1

One in 1st trimester (11-13 wks 6 d) and other in 2cd trimester (15-16 wks)

Question 2

When do you US for genetic screening?

Answer 2

11-13 wks 6 d for nunchal translucency

Question 3

What is the quad screen?

Answer 3

AFP, human chorionic gonadotropin, unconjugated estrogen (uE3), inhibin a

Question 4

When is the quad screen tested?

Answer 4

15-18 wks, But can be tested 15-21 wks

Question 5

Who do you offer quad screening to?

Answer 5

All women who present before 21 weeks

Question 6

What does the quad screen tell you?

Answer 6

Reports risk for open neural tube defects, trisomy 21, and trisomy 18

Question 7

How do you counsel in genetic screen?

Answer 7

Screen vs diagnostic test
Risk of down based on maternal age
Offer genetic counseling

Question 8

When do you not do the quad screen?

Answer 8

If pt is going to have an amniocentesis

Question 9

first trimester screening and tests?

Answer 9

Down Syndrome Screening
Uterine Size & Gestation
Ultrasound (fetal heart tones)
Chorionic Villus Sampling

Question 10

what is included in down syndrome screening?

Answer 10

Free B-Hcg
PAPP-A (Serum Pregnancy Associated Plasma Protein-A)
nuchal translucency

Question 11

what is a free b-hcg level indicative of?

Answer 11

Abnormally high or low may be indicative of abnormalities

Question 12

what does a low PAPPA possibly mean?

Answer 12

fetal down syndrome

Question 13

what does an abnormal nuchal translucency mean?

Answer 13

US @ 10-13 wks → ↑thickness is abnormal

Question 14

what if uterine size and gestation abnormal?

Answer 14

If abnormal, Chorionic Villus Sampling (CVS) or amniocentesis can be offered around 10-13 wks

Question 15

when can fetal Heart tone be detected?

Answer 15

10-12 wks by doppler

5-6 wks via US of fetus

Question 16

when does chorionic villus sampling need to be performed?

Answer 16

10-13wks

Question 17

when can chorionic villus sampling be offered?

Answer 17

May be offered to women including those with a prior child with chromosomal abnormality, maternal age >35 yrs, abnormal 1st or 2nd trimester maternal screening tests, abnormal US, prior pregnancy losses
+Advantage → Allows for option of early termination of pregnancy if abnormalities found
+Disadvantage → Performing increases the risk of spontaneous abortion

Question 18

when is triple screening done?

Answer 18

15-20 wks

Question 19

what is triple screening?

Answer 19

α- fetoprotein
β-hCG
Estradiol

Question 20

what disorder does a low AFP, high bhcg, and low estradiol dx?

Answer 20

down syndrome

Question 21

what does a high afp mea on a triople screen?

Answer 21

open neural tube defects, or multiple gestation

Question 22

what dose a low AFP, low Bhcg, and low estradiol mean?

Answer 22

trisomy 18 (often stillborn or dies w/in the first yr of life

Question 23

what is inhibin A?

Answer 23

high levels may be indicative of chromosomal abnormalities?

Question 24

what can US be used for?

Answer 24

check amniotic fluid level, fetal viability, and growth for gestational age