This study intends to randomly group the patients with advanced maternal age and poor ovarian response, and the study group will undergo polar body biopsy, and the next-generation sequencing(NGS) technology will be used to evaluate the polar body euploidy and then predict the euploidy of the oocyte. Embryo transfer priority according to the NGS test results and morphological scores. In the control group undergo routine culture and the transfer priority is determined according to the morphological score only. The transfer of frozen embryos at the cleavage or blastocyst stage was permitted. Cumulative live birth rate, miscarriage rate and time required to obtain a live birth up to two ovulatory cycles in a year.

Inclusion Criteria:

• patients between their 36th and 42st birthdays;
• absence of any type of genetic abnormality in the patient's personal and family history;
• MⅡ oocytes: 2-9 .

Exclusion Criteria:

• treatment involving donor oocytes;
• any type of genetic abnormality or family history of genetic abnormality in subject or partner;
• with assisted reproductive technology and pregnancy contraindications and with diseases that have a definite effect on pregnancy;
• poor embryo quality in previous cycles;
• Preimplantation genetic testing for aneuploidy(PGT-A) cycles;
• MⅡ oocytes ≥10 or ≤ 1;
• three or more previous failed IVF or Intracytoplasmic sperm injection(ICSI) cycles.