Group A was the hormone replacement combined with transplantation of umbilical cord mesenchymal stem cells group(test group).

Group B was the hormone replacement group (control group).

UC-MSCs (GMP grade, from Clinical Center for Stem Cell Research of the Affiliated Drum Tower Hospital of Nanjing University Medical School, licensed by the China Food and Drug Administration) are injected into the ovary of patients under transvaginal ultrasonographic (TVUS)-guidance. A total number of 10×106 cells, 5×106 for unilateral ovarian injection) is immediately preserved and transferred for direct injection. After vaginal sterilization, TVUS-guided transplantation is performed by two senior-level medical physicians, using a SIEMENS ACUSON ANTANES premium edition system (SIEMENS AG Healthcare Sector, Erlangen, Germany), equipped with a 6-10 MHz probe. The UC-MSC solution is injected into the ovary by using 21-G PTC needles (Hakko Medical Co, Japan) under TVUS guidance.

Follicular development and hormonal examination were performed 1 week before treatment and at 1, 2, and 3 weeks after treatment to evaluate the development of follicles. If there is no follicular development in the third week, stop the drug after 1 week, and contact the next treatment time after menstruation. During the follow-up period to half a year after the end of the last treatment, the follicular development activity rate was observed.

Ovarian artery blood flow spectrum PI; RI; S/D (L; R)

Clinical pregnancy was defined as diagnosed by increasing serum concentration of beta-HCG 14 days after embryo transfer, and the subsequent demonstration of an intrauterine gestational sac by ultrasonography on 30 days after embryo transfer