OB Pathology Flashcards
What is aneuploidy?
An unbalanced set of chromosomes
What is triploidy?
Presence of an additional set of chromosomes (69 total)
What is Trisomy?
Presence of an extra chromosome
What is autosomal dominant?
One parent is usually affected by trait and it is evident in each generation
What is autosomal recessive?
Parents are usually unaffected and the trait may appear to skip a generation.
What weeks do first trimester screening starts?
- 5- 13.5 weeks
- includes a NT ( >3 mm= abnormal ) ( inner to inner)
- Blood test of beta-hCG and PAPP-A
Know about PAPP-A and beta hCG?
produced by trophoblastic tissue, low levels may indicate abnormal implantation, poor placentation or Trisomy 21.
What weeks is Chorionic Villi Sampling done?
9 - 12 weeks
- samples placenta
What is involved in a quad screen?
- maternal serum alpha feto protein (MSAFP)
- hCG
- unconjugated estriol (uE3)
- Inhibin-A
What is AFP produced by?
Produced primarily by the fetal liver. Crosses placenta into maternal serum, can be easily identifiable.
What are the labs for Turners Syndome? ( Trisomy 18)
- decreased MS-AFP
- decreased hCG
- decreased uE3
What are the labs for Trisomy 21? ( Down syndrome)
- decreased MS-AFP
- increased hCG
- decreased uE3
- increased Inhibin A
What weeks is a amniocentesis done?
- 16 weeks gestation
- evaluate fluid levels of AFP
When does the blastocyst implant in the endometrium?
- 7 days after fertilization
- outer lining consists of trophoblasts, produces progesterone to extend life of corpus luteum
What is a morula?
- located at isthmus
- enters uterus 4 days after fertilization
What is a Blastomere?
- dividing fertilized ovum
- located within ampulla of fallopian tube
What is hCG?
Glycoprotein produced by trophoblastic cells and later by placenta
- doubles every 2 - 3 days
- PLATEAUS AROUND 8 - 9 WEEKS, THEN DECLINES
When does the heart start to beat?
by 6 weeks
What is decidual basalis?
where the blastocyst implants; maternal contribution to placenta
What is decidual capsularis?
closes over and surround the blastocyst
What is the decidual parietalis/ decidua vera?
hormonal influence on the uninvolved endometrial tissue
How much does the gestational sac grow per day?
1 mm / day
What level does the hCG need to be to visualize a sac?
1000 - 2000 mIu/ml transvaginally
When is a yolk sac visible?
- 5 weeks LMP
- should be seen by 7 weeks