Jiexiu Chen ¹ Xumei Kong ² Zonghui Luan ² Yu Qiu ^2,3 Shiqi Chen ² Jesse Li-Ling ⁴ Yan Gong ^2*

• ¹ Department of Clinical Pharmacy, Sichuan Provincial Hospital for Women and Children, Chengdu, China
• ² Department of Reproductive Medicine, Sichuan Provincial Hospital for Women and Children, Chengdu, China
• ³ Chengdu Medical College, Chengdu, Sichuan, China
• ⁴ Department of Medical Genetics, West China Second University Hospital, Sichuan University, Chengdu, China

Background: Growth hormone (GH) could improve the outcomes of in vitro fertilization and embryo transfer (IVF-ET) in patients with decreased ovarian reserve (DOR), but which age group will benefit the most has remained controversial. This study aims to explore the outcome of IVF-ET among differently aged patients with DOR treated with GH.: A total of 846 patients with DOR undergoing IVF-ET from May 2018 to June 2023 at the Reproductive Medicine Center of Sichuan Provincial Women's and Children's Hospital were prospectively enrolled. The patients were divided into group A (< 35 year old, n = 399), group B (35 ~ 40 year old, n = 286), and group C (> 40 year old, n = 161). Each group was sub-divided into: the GH part and Control part, with the former receiving pretreatment with GH 4 IU/d on day 2 of the previous menstrual cycle before the injection of gonadotrophin (Gn) until the trigger day. The ovarian stimulation protocol was gonadotrophin-releasing hormone antagonist (GnRH-A) or long acting GnRH agonist protocol. The quality of oocytes and embryos, and the outcome of pregnancy were compared.In group B, the number (1.16 ± 1.35 vs. 0.74 ± 1.06) and rate (34.27% vs. 23.90%) of highquality cleavage embryos, rates of implantation (32.37% vs. 22.35%), clinical pregnancy (48.98% vs. 33.67%) and live birth (44.90% vs. 29.59%) were significantly higher, whereas canceled oocyte retrieval rate was significantly lower (1.49% vs. 6.58%) in the GH part than those of the Control part (P < 0.05). In group B, the duration and dose of Gn, number of oocyte retrieved, and rates of normal fertilization, cleavage embryo, blastocyst, high-quality blastocyst and early miscarriage were not significantly different between the GH and Control parts (P > 0.05). In groups A and C, no significant difference was detected in the quality of embryos and outcomes of embryo transfer with or without pretreatment (P > 0.05).: GH could improve the quality of embryos and live birth rate for the patients with DOR aged 35 ~ 40 years old.