The objective of this study is to explore whether non-invasive chromosome screening (NICS) can be used as an effective indicator for embryos selection besides morphology through a multicenter randomized controlled trial, by comparing the differences of live birth rate, pregnancy rate and miscarriage rate between the two groups of embryo selection by "NICS+ morphology" and embryo selection only by "morphology" in IVF cycle.

Chromosomal abnormalities commonly exist in early human embryos, and often cause embryo implantation failure and pregnancy loss in in-vitro fertilization (IVF) treatments. Preimplantation genetic testing for aneuploidies (PGT-A) by comprehensive chromosome screening (CCS) has been widely applied in IVF practices to select embryos with normal ploidy. Although multiple clinical trials have demonstrated improved clinical outcomes with PGT-A, it's in controversial for whether PGT-A is truly worthwhile to be offered to all IVF patients. One of the main concerns is that it involves an embryo biopsy procedure, which is invasive and the long-term safety issue of the embryo biopsy remains to be fully investigated.

In recent years, researchers have found that the spent medium of embryo culture contains trace amount of cell-free DNA, which may reflect the ploidy of the embryo. The non-invasive chromosome screening (NICS) approach utilizing spent culture medium samples has been evaluated in studies. However, the clinical value of NICS as a new effective indicator to evaluate embryo competence so far has not been justified by randomized clinical trials.

The main purpose of this project is to verify whether NICS can be used as a new effective indicator for evaluating embryo developmental potential through multi-center, randomized clinical trials

Inclusion Criteria:

1. Infertile couples receiving IVF- ICSI procedure for assisted reproduction cycle
2. Female age: 35 - 42 years old
3. Women receiving controlled ovarian hyperstimulation treatment (including ultra-long protocol、long-protocol 、short protocol treatment with GnRH agonist and GnRH antagonist treatment protocol); and the number of oocytes ≥6; The female BMI is from 18 to 30kg/m2.
4. Culture embryos to blastocyst stage and all the blastocysts will be single cryopreserved.
5. Single frozen-thawed blastocyst Transferred for the first time
6. The number of blastocysts ≥2, morphology grade (above 4BC/4CB)
7. Written informed consent

Exclusion Criteria:

1. One of couples with IVF or ICSI contraindications(such as poorly controlled type I or type II diabetes; liver disease or dysfunction; kidney disease or renal function abnormality; significant anemia; history of deep venous thrombosis, pulmonary embolus; history of cerebrovascular accident; uncontrolled hypertension or diagnosed heart disease; history of cervical, endometrial or breast cancer; undiagnosed vaginal bleeding.)
2. PGT cycles
3. Women who have pathologies or malformations that affect the pregnancy outcome: genital malformations, untreated hydrosalpinx, untreated uterine infections, intramural myomas > 4cm , benign tumor of pelvic and abdominal cavity> 4cm, intimal thickness<8mm, pituitary tumors and malignant tumors of various tissues and organs during the patient's participation in the study
4. Untreated hyperprolactinemia, thyroid disease, adrenal disease
5. Women with endometrial polyps that were not treated before embryo transfer

IVF patients

Data may be shared with proper internal and ethical approval. De-identified data may also be shared with approved study investigators.

After the study has been completed

Proper internal and ethical approval; protect patient confidentiality; approve by study investigators