TY  - CHAP
M1  - Book, Section
TI  - Ultrasound of the Fetus at 11 to 18 Weeks
A1  - Monteagudo, Ana
A1  - Agten, Andrea Kaelin
A1  - Rebarber, Andrei
A1  - Timor-Tritsc, Ilan E.
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.
Y1  - 2017
N1  - 
T2  - Fleischer's Sonography in Obstetrics and Gynecology: Textbook and Teaching Cases, 8e
AB  - The  anatomical  survey,  as  well  as  the  understanding  of  the  developmental  anatomy  and  detection  rates  of  fetal  anomalies,  has  evolved  over  the  last  30  years  as  the  result  of  more  advanced  and  sophisticated  ultrasound  technologies.  Over  the  last  25  years,  18  weeks  has  been  considered  by  many  to  be  the  ideal  or  “gold-standard”  gestational  age  to  perform  the  first,  and  at  times  the  only,  anatomical  survey.  There  are  numerous  advantages  to  performing  the  scan  at  this  gestational  age:  the  fetus  is  large  enough  to  be  imaged  easily  using  transabdominal  (TA)  sonography,  and  most  anomalies  are  present  and  can  be  detected.  The  disadvantage  of  using  this  gestational  age  for  the  anatomical  survey  is  that  maternal  body  characteristics  such  as  abdominal  obesity,  uterine  fibroids,  and  fetal  position  can  at  times  preclude  adequate  imaging  of  the  fetal  structures,  which  can  result  in  an  incomplete  scan.  This,  in  turn,  necessitates  a  follow-up  scan.  This  need  for  follow-up  scans  has  resulted  in  a  gradual  shift  of  the  18-week  anatomy  scan  to  be  performed  at  20  to  22  weeks.  Therefore,  the  “18-week  anatomy  scan”  has  become  a  brand  name  for  the  sometimes  only  detailed  anatomical  survey  that  in  many  practices  is  carried  out  typically  at  around  20  weeks  or  anytime  between  18  and  22  weeks  of  gestation.  
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - obgyn.mhmedical.com/content.aspx?aid=1151031201
ER  -