IVF III generally includes the following steps: 1) ovulation promotion; 2) egg retrieval; 3) ICSI insemination; 4) blastocyst culture (5 days); 5) blastocyst biopsy (3-10 cells from trophoblast ectoderm for genetic diagnosis); 6) blastocyst freezing; 7) preimplantation diagnosis, screening for normal embryos (mainly using gene chip technology to diagnose structural and numerical chromosomal abnormalities in embryos) The accuracy is 95%, with the possibility of false positives and false negatives, and prenatal diagnosis is required to confirm the diagnosis; 8, normal blastocyst recovery and transfer; 9, pregnancy diagnosis; 10, prenatal diagnosis, i.e., chorionic villus biopsy in early pregnancy or amniocentesis in mid-pregnancy Amniocentesis to check fetal chromosomes or genes. Those with abnormal prenatal diagnosis may still face miscarriage or induction of labor.