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Second‐trimester Down syndrome maternal serum marker screening: a prospective study of 11 040 twin pregnancies
Author(s) -
GarchetBeaudron Aurélie,
Dreux Sophie,
Leporrier Nathalie,
Oury JeanFrançois,
Muller Françoise
Publication year - 2008
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.2145
Subject(s) - obstetrics , medicine , second trimester , prospective cohort study , down syndrome , twin pregnancy , first trimester , prenatal diagnosis , pregnancy , gynecology , fetus , genetics , biology , psychiatry
Objective To analyze the value of Down syndrome (DS) second‐trimester maternal serum screening in large series of twin pregnancies. Methods Prospective study of second‐trimester maternal serum markers [alpha fetoprotein (AFP) and free β‐human chorionic gonadotrophin (β‐hCG)] in 11 040 twin pregnancies, 27 of which were trisomy 21‐affected. Comparison with 64 815 singleton pregnancies, of which 86 were trisomy 21‐affected. Markers were expressed in multiple of median (MoM) corrected by a previously defined coefficient (2.1 for AFP and 2.07 or 2.16 for free β‐hCG, dichorionic or monochorionic, respectively). Results Trisomy 21 frequency was 1/649 for twins and 1/754 in singletons (NS). Mean detection rate was 63% (71% when both twins were affected and 60% when one was affected), versus 74.4% in singletons. False‐positive rates were 10.8% in twins versus 10.3% in singletons (NS). No significant differences in MoM AFP and free β‐hCG values were noted between twins and singletons (0.92 and 0.78 for AFP and 1.54 and 2.68 for free β‐hCG, respectively). Conclusion Our study demonstrates that second‐trimester DS maternal serum marker screening can be performed in twin pregnancies. Copyright © 2008 John Wiley & Sons, Ltd.