Assessment of fetal status in multiple gestation pregnancies using interphase FISH

The use of fluorescence in situ hybridization (FISH) for women with multipl e gestation pregnancies has been evaluated. Women were referred for chromos ome analysis because of advanced maternal age, abnormal ultrasound findings or a positive family history and/or prior to fetal reduction. FISH was suc cessfully applied to all specimens obtained by amniocentesis or chorionic v illus sampling (CVS). Based on FISH results, fetal-fetal contamination of s pecimens following CVS was 11.55 in twin pregnancies and 16% in triplet or higher multiples. FISH detected trisomy 21 in three cases with no false neg atives or positives. Whereas FISH may provide rapid and useful assessment o f fetal status in decision-making regarding fetal reduction, the present st udy also highlighted the obstetrical difficulty of ensuring a sample repres entative of each fetus following CVS in addition to the possibility of not identifying clinically significant chromosome aberrations using currently a vailable FISH probes. Copyright (C) 2001 John Wiley & Sons, Ltd.