Prolonged Protocol of Early Follicular or Mid Luteal Phase

Inclusion Criteria:

1. Tubal factor infertility;

2. polycystic ovary (PCO) or polycystic ovary syndrome (PCOS) patients;

3. Patients of mild to moderate endometriosis；

4. Oligoasthenospermia in male；

5. More than 5 antral follicle count (AFC) on both ovaries；

6. Unexplained infertility: there is a history of no contraception and pregnancy for morethan 1 year, no clear cause of infertility such as ovulation, fallopian tube,endometrium and male factors is found, or the above factors return to normal aftertreatment.

Exclusion Criteria:

1. History of adverse pregnancy and childbirth；

2. Unilateral ovariectomy；

3. Uterine malformation, intrauterine adhesion, submucous myoma；

4. Chromosomal abnormality of both husband and wife；

5. Patients with contraindications of assisted reproductive technology or pregnancy: suchas uncontrolled diabetes mellitus, undiagnosed liver and kidney dysfunction, historyof deep vein thrombosis, history of pulmonary embolism, history of cerebrovascularaccident, uncontrolled hypertension, heart disease, suspected cervical cancer,endometrial cancer, breast cancer or previous history, undetermined vaginal bleeding;

6. Unable to be regularly follow up；

7. Participating in other clinical trials；

8. No fresh single blastocyst transfer.