It is still a big difficult clinical problem for patients with poor ovarian reserve undergoing in vitro fertilization. The decrease in both quality and quantity of egg are the main cause for poor clinical prognosis. Growth hormone (GH) is currently one of the main adjuvant for improving pregnancy outcomes in patients with POR, and the investigators' previous retrospective study suggested GH was effective in live birth rate in subgroup of patients with POR older than 35 years old. To further figure out the mechanism of GH effectiveness in POR patients and the effect on clinical outcomes in POR patients, the investigators designed this prospective observational cohort study.

Inclusion Criteria:

For patients with poor ovarian response, the criteria is based on POSEIDON criteria[1]:

1. low ovarian reserve(AMH <1.2ng/ml, or AFC <5);
2. younger than 40.

For patients with normal ovarian reserve, the criteria is as follow:

1. Patients who are between 20-40 years old;
2. clinical diagnosis of non-functional fallopian tube;
3. regular menstrual cycles.

Exclusion Criteria:

1. BMI ≥28kg/m2;
2. medical diseases such as endocrine and metabolic diseases, autoimmune disease, etc;
3. ovarian neoplasm that ≥4 cm in diameter and has no clear pathological diagnosis by surgery;
4. adenomyosis or endometriosis confirmed by surgery;
5. untreated abnormal intrauterine environment, such as uterine effusion, endometritis, etc;
6. untreated hydrosalpinx;
7. polycystic ovary syndrome.

The study population includes patients diagnosed as POR based on POSEIDON criteria and with low ovairan reserve, as well as patients with normal ovairan reserve seeking for ART help due to pelvic tubal factors.