Pregnancy

Question 1

The concentration of ________ in amniotic fluid is a reflection on the severity of fetal hemolysis.

Answer 1

Unconjugated bilirubin

Question 2

What is the maximal absorbance of bilirubin, when assessing by scanning spectrophotometry?

Answer 2

450 nm

Question 3

What are two important factors for Amniotic fluid specimen collection?

Answer 3

• Blood contamination (absorbance peak of oxyhemoglobin at 410 nm can affect magnitude of peak at 450 nm)
• Protected from light (causes degradation of bilirubin)

Question 4

What produces Human chorionic gonadotropin?

Answer 4

• Placenta
• Tumors
• Pituitary gland (small amounts during menopause)

Question 5

What is the structure of hCG?

-What shares same structure?

Answer 5

Heterodimer of a alpha and a beta chain

• Alpha chain same as TSH, FSH, LH
• Beta chain is unique

Question 6

A false positive hCG is most often due to what?

Answer 6

Heterophile antibody interference

Question 7

• When does hCG become detectable?

- What are the levels?

Answer 7

• 6-8 days post-conception

- 10-50 mIU/mL

Question 8

• In normal pregnancy, hCG should double how often?

- When does it peak?

Answer 8

• 48 hours
• End of first trimester

*Decreases gradually and by early 2nd trimester plateus

Question 9

An abnormal hCG dynamic is defined as what?

What does this suggest?

Answer 9

• Failure to rise 66% in 48 hours
• Ectopic or nonviable intrauterine pregnancy

*20% of ectopic show normal rise

Question 10

After removal of an ectopic pregnancy, how long does hCG normally remain elevated?

Answer 10

Several weeks

Question 11

An abnormally high hCG is seen in what condition?

Answer 11

Gestational Trophoblastic disease (GTD)

-Molar pregnancy

Question 12

hCG is typically higher in complete or partial moles?

Answer 12

Complete moles have higher hCG

Question 13

What is the management following evacuation of a molar pregnancy?

Answer 13

• hCG levels monitored Weekly until undetectable for 3 consecutive weeks
• Then measured monthly for 1 year

Question 14

After evacuation of an uncomplicated molar pregnancy, how long does hCG remain detectable?
-When should persistent GTD be suspected?

Answer 14

10 weeks

-if hCG plateaus or rises, then persistent GTD is supected

Question 15

Quad Screen:

-Markers

Answer 15

Markers:

• Maternal serum hCG
• a-fetoprotein (AFP)
• unconjugated Estriol (uE)
• Inhibin A (DIA)

Question 16

Quad Screen:

• When
• How is risk calculated
• Sensitivity for Downs

Answer 16

• 2nd trimester (18 weeks)
• Analytes and maternal age
• 78%

Question 17

1st Trimester Test:

• Markers
• Sensitivity
• Time

Answer 17

• hCG
• PAPP-A
• Nuchal fold translucency (NT) thickness
• When combined with maternal age, overall sensitivity is 83%
• 10-13 weeks

Question 18

In Downs, is the Nuchal Fold Transulcency Thickness increased or decreased?

Answer 18

Increased

Question 19

What is the serum Integrated Screen?

-Sensitivity

Answer 19

Combined 1st and 2nd trimester serum testing

-when combined with maternal age and NT, overall sensitivity is 88%

Question 20

Quad screen levels in trisomy 21 (Downs).

Answer 20

• hCG - High
• AFP - Low
• Estriol - Low
• Inhibin - High

Question 21

Quad screen levels in trisomy 18 (Edward syndrome).

Answer 21

• hCG - Low
• AFP - Low
• Estriol - Low

Question 22

Quad screen levels in neural tube defect (NTD).

Answer 22

• hCG - Normal
• AFP - High
• Estriol - Low

Question 23

T/F: Bacterial vaginosis is independently associated with preterm labor.

Answer 23

True

Question 24

What is true regarding Fetal Fibronectin and preterm birth.

Answer 24

Absence of FF has very high Negative Predictive value and can exclude impending preterm birth.

*A positive result suggests preterm labor, but the overall PPV is low

Question 25

Where is fetal fibronectin normally found?

Answer 25

Placental fetomaternal surface

Question 26

What other test has similar diagnostic accuracy to fetal fibronectin?

Answer 26

Cervical Length assessed by Transvaginal Cervical US

Question 27

When is fetal lung maturity (FLM) generally achieved?

Answer 27

37 weeks gestation

Question 28

What has an accelerating effect on FLM?

Answer 28

Excess corticosteroids | -stress of complicated pregnancy

Question 29

What effect does maternal DM have on FLM?

Answer 29

Delays

Question 30

What is the Lecithin/Sphingomyelin ratio that indicates FLM?

Answer 30

>2.5:1 (F/S ratio)

Question 31

In pregnancies complicated by maternal diabetes, a ratio of 2.5:1 (L/S) is less predictive of FLM. WHat test is more reliable in this setting?

Answer 31

Phosphatidylglycerol concentration

Question 32

What effect does meconium have on the L:S ratio? | -Blood?

Answer 32

Falsely decreases *Blood normalizes the L:S ratio to ~1.5

Question 33

When is Phosphatidylglycerol (PG) first detected? What is its significance?

Answer 33

- 35-36 weeks | - Presence is indicative of FLM

Question 34

What effect does blood and meconium have on PG?

Answer 34

No effect *however, PG is a late marker for FLM, which limits its utility in prematurity

Question 35

Surfactant Lamellar Bodies (LBC): - How are they counted? - What level is predictive of FLM? - Blood and Meconium effects?

Answer 35

- Same size as platelets (use platelet channel of cell counter) - LBC >50,000 - Blood - Decreases LBC - Meconium - Increases LBC

Question 36

T/F: Estrogen causes an increase in transport proteins such as thyroid binding globulin (TBG).

Answer 36

True

Question 37

When does relative insulin resistance emerge in pregancy? What causes this?

Answer 37

- early 3 trimester | - human Placental Lactogen (hPL) has antiinsulin effects similar to growth hormone

Question 38

What happens to sodium and potassium levels throughout pregnancy?

Answer 38

remain relatively constant

Question 39

What happens to calcium levels in pregnancy?

Answer 39

- Total calcium levels DECREASE (10%) d/t physiologic hypoalbuminemia - Ionized calcium levels remain unchanged

Question 40

What happens to Hct/Hb in pregnancy?

Answer 40

- Hct - decreases (4-7%) | - Hb - decreases (1.5-2 g/dL)

Question 41

What happens to BUN in pregnancy?

Answer 41

Decreases (50%)