First-Trimester Down Syndrome Screening in Renal-Transplanted Pregnant Women: Blood Creatinine Levels Impact False-Positive Rate.

OBJECTIVE

Over the past few decades, several thousand pregnancies following kidney transplantation have been monitored but few studies have reported on first-trimester Down syndrome screening. This study aimed to assess the performance of such screening and its relationship with renal function.

METHOD: We retrieved data on 16 pregnancies after kidney transplantation and 30 controls matched for age, weight and gestational age. First-trimester blood creatinine levels were systematically researched. Among other variables, multiples of the median (MoM) values for free-βhCG, pregnancy-associated plasma protein-A (PAPP-A), nuchal translucency were compared. After statistical review, we combined our cases group with that of a previous study to obtain a cohort of 27 post-transplantation pregnancies to explore correlations between variables.

RESULTS

Median values of fβ-hCG MoM of cases and controls were significantly different (2.02 vs. 0.92; p < 0.001) whereas those of PAPP-A and NT MoM were not. Screen positive rate (SPR) were respectively 44% and 17% (cut-off 1/1000). Linear regressions were observed for fβ-hCG MoM and creatinine, but not for PAPP-A, in our initial case group (r = 0.699, p = 0.025) and the merged group (r = 0.724, p < 0.001).

CONCLUSION

We confirmed a specific profile for first-trimester screening variables in first-trimester post-transplantation pregnancies and the impact of renal function, through creatinine levels, on SPR.