Blastocyst Euploidy Assessment and Conditioned embryO traNsfer

Inclusion Criteria: * Patient undergoing in vitro fertilization (IVF) * Normal uterine function by ultrasound and absence of hysteromyoma * Regular menstrual cycle of 25-35 days * Normal hormone levels (WHO standard) for LH, PRL, E2, PROG, TEST and TSH * FSH 1-12 IU/L and follicle number \> 5 on day 2-3 of menstrual cycle * Minimum of 3 blastocysts on day 5 of embryo development * Signed consent form Exclusion Criteria: * Known endometriosis * Abnormal vaginal bleeding with no known cause * Known genital organ system malformation, unsuitable to conceive * Known currently active pelvic inflammation * Abnormal liver, kidney lab results, with clinical implications. * Known endocrine or metabolic disorders (pituitary gland, adrenal glands, pancreas, liver or kidney） * Known ovarian, breast, uterine, adrenal glands, pituitary gland or hypothalamus tumor * Known abnormal cervical cancer lesions, with clinical implications, within one year before PGS * History of chemo- or radio-therapy * Seropositive for HIV, Hep B, Hep C or TPPA/RPR (Syphilis) * Known ovarian poor response in previous cycles, i.e. after administration of GnRH for \> 20 days * More than 2 implantation failures * More than 2 miscarriages * Known altered parental karyotype such as Robertsonian or reciprocal translocation * Use of sperm or oocyte donors * Severe male factor (surgical retrieval of sperm) * Preimplantation genetic diagnosis cycles for single gene diseases or sex selection * Participation in other IVF research studies * Patient refusal or inability to follow the protocol for any good reason, including clinical visit or lab test