RT Book, Section
A1 Abramowicz, Jacques S.
A1 Hicks, Melissa M.
A1 Breathnach, Fionnuala M.
A1 Malone, Fergal D.
A2 Fleischer, Arthur C.
A2 Abramowicz, Jacques S.
A2 Gonçalves, Luis F.
A2 Manning, Frank A.
A2 Monteagudo, Ana
A2 Timor, Ilan E.
A2 Toy, Eugene C.
SR Print(0)
ID 1151035445
T1 First Trimester Screening
T2 Fleischer's Sonography in Obstetrics and Gynecology: Textbook and Teaching Cases, 8e
YR 2017
FD 2017
PB McGraw-Hill Education
PP New York, NY
SN 9781259641367
LK obgyn.mhmedical.com/content.aspx?aid=1151035445
RD 2024/04/18
AB Key  TermsAneuploidy:  the  state  of  having  a  chromosome  number  that  is  not  a  multiple  of  the  haploid  number.Combined  first  trimester  screening:  computation  of  risk  assessment  for  fetal  aneuploidy  using  a  combination  of  sonographic  evaluation  of  fetal  nuchal  translucency  with  the  following  maternal  serum  biochemical  markers:  pregnancy-associated  plasma  protein-A  (PAPP-A)  and  either  the  free  β-subunit  of,  or  intact,  human  chorionic  gonadotrophin  (fβ-hCG  or  t-hCG).Contingent  screening:  also  known  as  “sequential  contingency”  screening—a  screening  strategy  that  requires  second  trimester  screening  only  in  those  women  whose  first  trimester  results  are  reported  as  “borderline.”  Subsequent  second  trimester  screening  incorporates  earlier  screening  results  in  risk  calculation.Fully  integrated  screening:  a  screening  strategy  that  assigns  risk  based  on  the  combination  of  first  and  second  trimester  screening  results,  with  nondisclosure  of  results  until  the  completion  of  second  trimester  testing.Independent  sequential  screening:  the  combination  of  first  and  second  trimester  screening  results,  but  with  disclosure  of  first  trimester  results,  such  that  only  patients  with  a  negative  first  trimester  screen  are  recalled  for  second  trimester  testing.  The  second  trimester  screening  results  do  not  take  into  account  the  results  of  the  earlier  screen.Multiple  of  the  median  (MoM):  the  division  of  a  measurement  by  the  median  value  for  the  normal  population.Nuchal  translucency:  hypoechoic  area  in  the  fetal  neck  region,  the  thickness  of  which  is  measured  sonographically  between  11  and  14  weeks’  gestation  as  a  marker  for  fetal  aneuploidy.Quadruple  (“quad”)  test:  second  trimester  measurement  of  serum  α-fetoprotein  (AFP),  unconjugated  estriol  (uE3),  human  chorionic  gonadotrophin  (hCG),  and  inhibin  A.Septated  cystic  hygroma:  enlargement  of  the  hypoechoic  space  at  the  back  of  the  fetal  neck,  extending  along  the  length  of  the  fetal  back,  with  clearly  visible  septations.Stepwise  sequential  screening:  a  screening  strategy  whereby  patients  are  offered  first  trimester  results,  and  subsequently  first  trimester  markers  are  included  in  the  second  trimester  risk  assessment.Noninvasive  DNA  screening  (NIDS):  a  screening  strategy  employable  after  10  weeks’  gestation  quantifying  circulating  cell-free  DNA  (ccfDNA)  in  maternal  serum  to  assess  the  risk  for  fetal  aneuploidy.Circulating  cell-free  DNA  (ccfDNA):  free-floating  fragmented  DNA  in  the  maternal  serum.  During  pregnancy,  approximately  3%  to  13%  of  the  total  cell-free  maternal  DNA  is  from  placental  trophoblasts.  This  may  also  be  referred  to  as  cell-free  fetal  DNA.  The  percentage  of  the  total  cell-free  maternal  DNA  that  is  placental  in  origin  is  termed  the  fetal  fraction.