RESUMEN
<p><b>OBJECTIVE</b>To estimate the value of blastocyst culture for preimplantation genetic diagnosis (PGD).</p><p><b>METHODS</b>Day 3 embryos were biopsied and analyzed with fluorescence in situ hybridization (FISH) technique. Embryos with normal FISH results were cultured into blastocysts, and the ones with better morphology scores were transferred. Fourteen embryos with abnormal FISH results were cultured into blastocysts. Part of the cells taken from the blastocysts were amplified by whole genomic amplification (WGA) and assessed by array-based comparative genomic hybridization (array-CGH) analysis.</p><p><b>RESULTS</b>Six blastocysts with normal FISH results were transferred in 5 cycles. Four healthy babies of 3 cycles were delivered. Another one was a singleton pregnancy but with embryo growth arrest, whose villus karyotype was normal. Fourteen embryos with abnormal FISH results were cultured into blastocysts and analyzed by array-CGH. Six blastocysts were normal by array-CGH.</p><p><b>CONCLUSION</b>FISH combined with blastocyst culture may further ensure the accuracy of PGD result. Detection at the blastocyst stage can avoid false positive results and mosaic interferences on Day 3 stage and are therefore more authentic.</p>