Studies on humans have shown that approximately 40-50% of early pregnancy loss results from unbalanced chromosome make-up in the conceptus. A majority of these losses occurs prior to implantation or within the ﬁrst 4 weeks of pregnancy. The fluorescence in situ hybridization (FISH) technique using chromosome-specific DNA probes may be used to assess the numerical and structural chromosome aberrations in interphase cells.
In situ hybridization is a technique that allows the visualization of specific nucleic acid sequences within a cell. Specifically, DNA fluorescence in situ hybridization (FISH) involves the precise annealing of a single stranded fluorescently labeled DNA probe to complementary target sequences. The hybridization of the probe with the cellular DNA site is visibile by direct detection using fluorescence microscopy.