The Effect of VitC on IVF Outcome of DOR Patients

Live births within 1 year after oocyte retrieval following embryo transfer; calculated as: (Final number of live births / Number of randomized participants) × 100%

(Number of singleton live births / Number of randomized participants) × 100%

(Number of women with twin live births / Number of randomized participants) × 100%

Presence of at least one gestational sac (including intrauterine and ectopic) confirmed by transvaginal ultrasound 28-30 days after embryo transfer; includes singleton pregnancy rate and twin pregnancy rate (twin and multiple pregnancy rates should be reported along with pregnancy loss rate)

Presence of at least one gestational sac with fetal heartbeat confirmed by transvaginal ultrasound at 12 weeks after embryo transfer.

or participants who achieved live birth, the time from intervention initiation to clinically confirmed pregnancy (confirmed by ultrasound 30 days after transfer). Survival analysis will be used to compare between intervention and control groups.

Number of oocytes retrieved

On Day 1 post-retrieval, oocytes with two pronuclei (2PN) are counted as normally fertilized.

No oocytes in the current treatment cycle show 2PN after fertilization or injection.

On Day 3 post-retrieval, embryos with ≥4 cells and ≤30% fragmentation are considered usable.

On Day 3 post-retrieval, 2PN-derived embryos with ≥6 cells and ≤10% fragmentation are classified as high-quality.

The number of gestational sacs (including intrauterine and ectopic) detected by transvaginal ultrasound 28-30 days after embryo transfer.

A pregnancy occurring outside the uterine cavity, diagnosed by ultrasound, surgical visualization, or histopathology.

Spontaneous loss of an intrauterine pregnancy before 20 weeks of gestation. This should occur after ultrasound confirmation of a viable pregnancy.

Fetal death occurring after 20 weeks of gestation, before complete expulsion or extraction. Death is determined by the absence of breathing or other signs of life (e.g., heartbeat, umbilical cord pulsation, or definite voluntary movement) after delivery.

Medical, surgical, or other artificial termination of an intrauterine pregnancy (including fetal reduction procedures).

OHSS is primarily characterized by cystic enlargement of the ovaries, increased vascular permeability, third-space fluid accumulation (resulting in ascites and pleural effusion), and localized or generalized edema.)

Including gestational diabetes mellitus, hypertensive disorders of pregnancy, antepartum hemorrhage, etc.

The number of weeks from fertilization to delivery, plus 14 days.

Birth occurring before 37 weeks of gestation (i.e., fewer than 259 days of pregnancy).

The weight of the newborn at birth. Abnormal birth weight includes: Low birth weight (LBW): <2,500 g Very low birth weight (VLBW): <1,500 g High birth weight (macrosomia): >4,000 g Very high birth weight: >4,500 g

Newborns with birth weight above the 90th percentile for their gestational age and sex.

Newborns with birth weight below the 10th percentile for their gestational age and sex.

Death of a live-born infant within 28 days after birth. This can be further categorized as:

Early neonatal death: Death occurring within the first 7 days of life. Late neonatal death: Death occurring between 8 and 28 days of life.

Structural, functional, or genetic abnormalities occurring during pregnancy, which may be identified prenatally, at birth, or postnatally, and may be life-threatening or fatal. Major congenital anomalies should be reported as infants with at least one major congenital anomaly detected. If a major birth defect is identified in a multiple pregnancy, it should be explicitly reported.

A single high dose (5-10 g) of vitamin C may cause transient osmotic diarrhea and/or abdominal bloating. However, the human body has a high tolerance, and even such high doses are generally safe. Typically, these symptoms gradually improve or disappear after continued use.

Hyperuricemia: Vitamin C can be partially metabolized into oxalate and dose-dependently increase oxalate levels in urine. High doses of vitamin C may temporarily increase uric acid excretion, while high-dose intravenous administration may stimulate polyuria. Therefore, the daily recommended dose of vitamin C should not exceed 1 gram. Urine routine tests will be conducted during follow-up.

Some studies have found that high-dose oral vitamin C significantly increases the risk of kidney stone formation in men by 41%. Additionally, long-term high concentrations of oxalate in urine may contribute to stone formation. Thus, high-dose vitamin C supplementation in at-risk populations may lead to urinary tract stones, as self-reported by participants.

Intravenous or high-dose oral vitamin C may induce hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency and worsen hemolysis in those with paroxysmal nocturnal hemoglobinuria. If such symptoms occur, vitamin C should be discontinued immediately, medical attention sought, and researchers contacted.