Nuchal translucency in pregnancies conceived after assisted reproduction technology.
OBJECTIVE
Nuchal translucency is one of the important markers in the first trimester during antenatal screening for fetal Down's syndrome. With the observation of alterations in biochemical markers in pregnancies conceived after assisted reproduction, this review presents current information related to the thickness of nuchal translucency in these pregnancies.


RESULTS
Early small studies did not demonstrate any discrepancy in the thickness of nuchal translucency in fetuses from assisted reproduction and from spontaneous pregnancies, but there has been recent evidence to suggest an increased level of nuchal translucency in singletons from various modes of assisted-reproduction technology. Nuchal translucency in twins following assisted reproduction did not, however, show a similar increase. Although the effect of chorionicity was not specifically addressed, nuchal translucency thickness in twins born after assisted reproduction was reported to be comparable to that in spontaneous singletons. It is possible that singletons and twins after assisted reproduction exhibit different antenatal behavior and pregnancy courses.


CONCLUSIONS
Similar to other biochemical markers of fetal Down's syndrome, nuchal translucency is increased in singletons after assisted-reproduction technology. Further studies on twin pregnancies, in particular dichorionic twins, are necessary before conclusive evidence can be drawn for multiple pregnancies.
Hui
Pui Wah
PW
Department of Obstetrics and Gynaecology, University of Hong Kong, Hong Kong. pwhui@graduate.hku.hk
Lee
Chin Peng
CP
Tang
Mary Hoi Yin
MH
Ho
Pak Chung
PC
D004314:Down Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D048208:Nuchal Translucency Measurement / Q000706:statistics & numerical data*; D011247:Pregnancy; D011272:Pregnancy, Multiple; D027724:Reproductive Techniques, Assisted / Q000009:adverse effects*; D014427:Twins