Inclusion Criteria:  Patients with normal ovarian function reserve (5 ≤ AFC ≤ 15, 1.2 ng/ml ≤ AMH ≤ 3.5 ng/ml). Patients with regular menstrual cycle (21-35 days) and normal ovulation. Initial IVF / ICSI treatment. At least one embryo or blastocyst available for transfer.  Exclusion Criteria:  Age ≥ 43 years old. Body mass index (BMI) ≥ 28 Kg/m2. "Freeze-all" strategy. Those using the natural cycle or mild stimulation for IVF/ICSI treatment. Individuals with severe hyperstimulation ovarian syndrome during controlled ovarian stimulation. Acceptors of donated oocytes or performed either In vitro Maturation (IVM) or blastocyst biopsy for Preimplantation Genetic Diagnosis (PGD) or Preimplantation Genetic Testing for Aneuploidies (PGT-A). History of two or more previous consecutive spontaneous abortions. History of two or more previous IVF-ET failures. Karyotype abnormalities. Polycystic ovary syndrome. Presence of a non-surgically treated hydrosalpinx, uterine cavity fluid or endometrial polyp and an ovarian endometriosis cyst requiring surgery, during ovarian stimulation. Congenital or acquired abnormalities of uterine anatomy. Combined contraindications to assisted reproductive technology or pregnancy, such as uncontrolled abnormalities of liver and kidney function, diabetes mellitus (glycosylated haemoglobin ≤7%, fasting blood glucose <10 mmol/L ), hypertension, thyroid disease, symptomatic heart disease, moderate to severe anaemia, history of malignancy or thromboembolism or propensity to thrombosis, severe psychiatric disorder, acute infections of the genitourinary system, sexually transmitted diseases, serious adverse habits such as drug abuse, exposure to teratogenic amounts of radiation, toxins, or drugs (such as prednisone or other hormones, adrenaline, antibiotics, or hypertension, cardiovascular, or antiviral medications) during the active procedure period , and uterine factor infertility or physical illness which prevents the ability to bear a pregnancy.