This randomized controlled trial enrolled women of advanced maternal age (≥35 years) undergoing ART, who were allocated to an intervention group (oral nicotinamide riboside, NR) or a control group (oral vitamin E, VitE) for a 2-month pre-ART intervention. The study systematically evaluated NR's regulatory effects on ovarian function and ART outcomes by measuring NAD+ levels in ovarian granulosa cells (GCs) and peripheral blood mononuclear cells (PBMCs), anti-Müllerian hormone (AMH) concentrations.

Patients received daily oral supplementation of either nicotinamide riboside (NR, 600 mg/day) or vitamin E (200 mg/day) for two consecutive months, initiated on day 2 of the menstrual cycle. Participants were enrolled if they planned to undergo in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) with a gonadotropin-releasing hormone (GnRH) antagonist protocol following the intervention period.

Biological Samples

Peripheral blood mononuclear cells (PBMC) were isolated from venous blood.

Follicular fluid containing granulosa cells and discarded oocytes were collected during routine oocyte retrieval procedures.

Hormonal and Ovarian Assessments

Baseline measurements: Blood samples were obtained on day 2-3 of the menstrual cycle prior to medication initiation to assess basal endocrine profiles (FSH, LH, E2, P, T, PRL) and anti-Müllerian hormone (AMH) levels.

Post-intervention measurements: Repeat hormonal evaluations and transvaginal ultrasound assessments (antral follicle count [AFC]) were performed on day 2-3 of the third menstrual cycle after two months of supplementation.

Inclusion Criteria:

1. Infertile women aged between 35 and 42 years;
2. 0.1 ng/mL <= AMH <= 1.1 ng/ml;
3. Pregnancy aids who plan to perform in vitro fertilization and embryo transfer (antagonist program);
4. Bilateral ovaries are present;
5. Patients who voluntarily signed the informed consent and agreed to be followed up according to the requirements of the study protocol.

Exclusion Criteria:

1. Adenomyosis and uterine fibroids compression of uterine uterine line;
2. Untreated bilateral hydrosalpinx;
3. Uncured endometrial disease;
4. Any pregnancy occurred within 3 months before screening;
5. Patients with clinically significant abnormal cervical examination results within 3 months before screening;
6. Use of fertility regulators (such as clomiphene citrate, GnRH, metformin or oral contraceptives) within 1 month before randomization;
7. Use hormone drugs within 1 month before randomization;
8. Patients with acute infection of urinary and reproductive system;
9. Patients with major systemic diseases, endocrine or metabolic abnormalities that are not suitable to participate in this study, as judged by the investigator;
10. According to the judgment of the investigator, the presence of uterus (such as submucosal uterine fibroids, intermural uterine fibroids larger than 3 cm or smaller than 3 cm but affecting uterine cavity morphology, untreated endometrial polyps, uterine adhesions, uterine malformations, and ASRM stage Ⅲ-Ⅳ endometriosis). Patients with clinically significant ovarian (e.g., polycystic ovaries, ovarian cysts > 4 cm, inability to retrieve eggs from both or one ovary) or adnexa (e.g., hydrosalpinx) abnormalities;
11. Patients with unexplained abnormal uterine bleeding;
12. Patients with a history of ovarian, breast, uterus, hypothalamus, pituitary and other malignant tumors;
13. Receive donor egg or embryo preimplantation genetic screening/embryo preimplantation genetic diagnosis (PGS/PGD);
14. Known past or current thromboembolic disease;
15. Have a known serious mental illness or fail to understand the purpose and methods of the clinical trial, or fail to comply with the study procedures;
16. Patients with contraindications or allergic history to the use of GnRH-a, r-hFSH, hCGα, progesterone;
17. Those who are addicted to alcohol, tobacco, drugs or drug abuse;
18. Being exposed to teratogenic amounts of radiation, poisons and drugs and in the action period;
19. Patients with liver function injury, that is, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were 2.5 times higher than the upper limit of normal values;
20. Persons who are HIV or syphilis positive;
21. Those with positive serum pregnancy tests;
22. Other reasons why the researcher considers it inappropriate to participate in the study. Suffers from a disease that is not suitable for the present assisted reproductive technology or for the present pregnancy;
23. Participants who had participated in other clinical trials within 3 months prior to screening.