Comparison of Development Rates for PGD/FISH Embryos Based on Gender

Abstract

Research in bovine and murine embryos suggests an increased development rate in male vs. female embryos. There has been some speculation that blastocyst ET weights gender due to this phenomenon but it has not been proved. With the introduction of IVF/PGD/FISH for aneuploidy screening, the ability to monitor human embryo development against gender can be realized. Because recent advances in PGD technologies have allowed fertility labs to look at the genetics, as well as the morphology, of embryos, this study also evaluates if embryo development in genetically abnormal embryos occurs at an increased rate to genetically normal embryos. A retrospective analysis of all PGD/FISH-Aneuploidy treatment embryos and their gender outcome from 2004, regardless of patient diagnosis. 599 embryos were evaluated based on their euploidy: Group A-euploid embryos; Group B- monsomic embryos; Group C- trisomic embryos; and Group D- complex abnormal embryos. All embryos were cultured in sequential media and isolated into individual culture drops for assessment of development. Only viable embryos were included in this study. The table below shows no significant difference in gender outcome within all study groups. Female embryos were XX and male XY, only. Embryos with abnormal sex chromosomes were excluded. Tabled 1 Tabled 1 118 blastocysts developed by day 5 of culture (20%). A blastocyst included early, full, and hatching blastocysts. Blastocyst development within the 4 study groups is shown in Table 2. There was no significant difference in development of blastocysts from male or female embryos or euploid (47%) vs. aneuploid embryos (53%; 63/118). Human male embryos do not appear to have a developmental advantage over female embryos in vitro, both having the same rate of blastocyst formation. However, euploid embryos develop to the blastocyst stage at an equal rate (467%) as aneuploid ones (53%; 63/118). This data corroborates previous published data that indicate blastocyst development does not eliminate abnormalities and suggests no gender skewing in either blastocyst culture or aneuploidy studies.