Premium
Biochemical screening for Down syndrome in pregnancies following renal transplantation
Author(s) -
Karidas C. N.,
Michailidis G. D.,
Spencer K.,
Economides D. L.
Publication year - 2002
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.294
Subject(s) - medicine , transplantation , creatinine , trisomy , amniocentesis , pregnancy , renal function , gestational age , aneuploidy , obstetrics , urology , gynecology , gastroenterology , fetus , prenatal diagnosis , biology , biochemistry , genetics , gene , chromosome
Objective To assess the performance of the double marker test [free β‐human chorionic gonadotrophin (β‐hCG) and alpha‐fetoprotein (AFP)] as a screening test for Down syndrome in pregnant patients who had a prior renal transplant. Design A retrospective study. Setting The Fetal Medicine Unit, Royal Free Hospital, London, UK. Methods Detailed records of 14 post‐renal transplant pregnancies were obtained from the Renal Unit of our hospital where the patients were followed up. The serum concentrations of urea, creatinine, free β‐hCG and AFP at the time of the double marker test were recorded, with a cut‐off point of 1:250 for the double marker test. A control group of 14 normal pregnancies matched for age, parity and gestational age was used. The Mann‐Whitney U ‐test and t ‐tests of unequal variance were applied to compare parameters of the study and the control groups. Results Two patients in each group were high risk for Down syndrome and amniocentesis revealed normal karyotype. No babies with Down syndrome were delivered in either group. Regression analysis showed significant correlation between free β‐hCG and urea concentrations ( p <0.001) and free β‐hCG and creatinine concentrations ( p <0.001), but not for AFP. Conclusions The present study demonstrates that residual renal function alterations persisting after renal transplantation can affect the levels of free β‐hCG and AFP, thus resulting in false‐positive screening for Down syndrome. First trimester nuchal translucency (NT) measurement in combination with second trimester ultrasonographic markers can be used in these patients, or alternatively the free β‐hCG levels should be corrected according to the serum creatinine levels. Copyright © 2002 John Wiley & Sons, Ltd.