False-positive quadruple screen test for trisomy 18 in a patient with a fetus with Bloom's syndrome.

In the literature, conflicting reports on the significance of false-positive maternal serum multiple marker testing for trisomy 18 are encountered; however, the biology of this finding is discussed infrequently. We present such a case in association with Bloom's syndrome in the fetus. The fetus had intrauterine growth restriction, seen early in the second trimester, oligohydramnios, and was delivered at 34 weeks of gestation for impending fetal compromise. We propose that the adverse outcome of the pregnancy with false-positive serum analyte testing for trisomy 18 might result from a small-sized placenta and perhaps pathology at receptor level.