Pregnancy Flashcards
(41 cards)
The concentration of ________ in amniotic fluid is a reflection on the severity of fetal hemolysis.
Unconjugated bilirubin
What is the maximal absorbance of bilirubin, when assessing by scanning spectrophotometry?
450 nm
What are two important factors for Amniotic fluid specimen collection?
- Blood contamination (absorbance peak of oxyhemoglobin at 410 nm can affect magnitude of peak at 450 nm)
- Protected from light (causes degradation of bilirubin)
What produces Human chorionic gonadotropin?
- Placenta
- Tumors
- Pituitary gland (small amounts during menopause)
What is the structure of hCG?
-What shares same structure?
Heterodimer of a alpha and a beta chain
- Alpha chain same as TSH, FSH, LH
- Beta chain is unique
A false positive hCG is most often due to what?
Heterophile antibody interference
- When does hCG become detectable?
- What are the levels?
- 6-8 days post-conception
- 10-50 mIU/mL
- In normal pregnancy, hCG should double how often?
- When does it peak?
- 48 hours
- End of first trimester
*Decreases gradually and by early 2nd trimester plateus
An abnormal hCG dynamic is defined as what?
What does this suggest?
- Failure to rise 66% in 48 hours
- Ectopic or nonviable intrauterine pregnancy
*20% of ectopic show normal rise
After removal of an ectopic pregnancy, how long does hCG normally remain elevated?
Several weeks
An abnormally high hCG is seen in what condition?
Gestational Trophoblastic disease (GTD)
-Molar pregnancy
hCG is typically higher in complete or partial moles?
Complete moles have higher hCG
What is the management following evacuation of a molar pregnancy?
- hCG levels monitored Weekly until undetectable for 3 consecutive weeks
- Then measured monthly for 1 year
After evacuation of an uncomplicated molar pregnancy, how long does hCG remain detectable?
-When should persistent GTD be suspected?
10 weeks
-if hCG plateaus or rises, then persistent GTD is supected
Quad Screen:
-Markers
Markers:
- Maternal serum hCG
- a-fetoprotein (AFP)
- unconjugated Estriol (uE)
- Inhibin A (DIA)
Quad Screen:
- When
- How is risk calculated
- Sensitivity for Downs
- 2nd trimester (18 weeks)
- Analytes and maternal age
- 78%
1st Trimester Test:
- Markers
- Sensitivity
- Time
- hCG
- PAPP-A
- Nuchal fold translucency (NT) thickness
- When combined with maternal age, overall sensitivity is 83%
- 10-13 weeks
In Downs, is the Nuchal Fold Transulcency Thickness increased or decreased?
Increased
What is the serum Integrated Screen?
-Sensitivity
Combined 1st and 2nd trimester serum testing
-when combined with maternal age and NT, overall sensitivity is 88%
Quad screen levels in trisomy 21 (Downs).
- hCG - High
- AFP - Low
- Estriol - Low
- Inhibin - High
Quad screen levels in trisomy 18 (Edward syndrome).
- hCG - Low
- AFP - Low
- Estriol - Low
Quad screen levels in neural tube defect (NTD).
- hCG - Normal
- AFP - High
- Estriol - Low
T/F: Bacterial vaginosis is independently associated with preterm labor.
True
What is true regarding Fetal Fibronectin and preterm birth.
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
