Single　oocyte　manipulation　in　microfluidic　channels　via　precisely　controlled　flow　is　critical　in　microfluidics-based　in　vitro　fertilization.　Such　systems　can　potentially　minimize　the　number　of　transfer　steps　among　containers　for　rinsing　as　often　performed　during　conventional　in　vitro　fertilization　and　can　standardize　protocols　by　minimizing　manual　handling　steps.　To　study　shape　deformation　of　oocytes　under　shear　flow　and　its　subsequent　impact　on　their　spindle　structure　is　essential　for　designing　microfluidics　for　in　vitro　fertilization.　Here,　we　developed　a　simple　yet　powerful　approach　to　(1)　trap　a　single　oocyte　and　induce　its　deformation　through　a　constricted　microfluidic　channel,　(2)　quantify　oocyte　deformation　in　real　time　using　a　conventional　microscope　and　(3)　retrieve　the　oocyte　from　the　microfluidic　device　to　evaluate　changes　in　their　spindle　structures.　We　found　that　oocytes　can　be　significantly　deformed　under　high　flow　rates,　e.g.,　10　mu　L/min　in　a　constricted　channel　with　a　width　and　height　of　50　and　150　mu　m,　respectively.　Oocyte　spindles　can　be　severely　damaged,　as　shown　here　by　immunocytochemistry　staining　of　the　microtubules　and　chromosomes.　The　present　approach　can　be　useful　to　investigate　underlying　mechanisms　of　oocyte　deformation　exposed　to　well-controlled　shear　stresses　in　microfluidic　channels,　which　enables　a　broad　range　of　applications　for　reproductive　medicine.