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Submitted August 13, 2001; accepted December 10, 2001
Purpose:To evaluate the impact of ascorbic acid of different doses as additional support during luteal phase in infertility treatment by means of a prospective, randomized, placebo-controlled, group comparative, double-blind study.
Methods: Voluntary daily oral intake of either ascorbic acid (1, 5, or 10 g/day) or Placebo for 14 days after follicle aspiration for IVF-ET procedure. Data was obtained on 620 cases of women, age <40 years, undergoing first IVF-embryo transfer cycles in two private outpatient infertility clinics. All women were stimulated by the same protocol. The mean age was 31.73 (ss4.4 SD) years.
Results:Nodifferences in clinical pregnancy rate and implantation rate were noted in statistical logistic regression analysis between the four intake groups.
Conclusions: There was no clinical evidence of any beneficial effect, as defined by main outcome measures, of ascorbic acid on IVF-ET. Our data suggest there is no obvious value of high dosed intake of vitamin C during luteal phase in infertility treatment.
KEY WORDS: Ascorbic acid; fertility; IVF; luteal phase.
INTRODUCTION
Ascorbic Acid (AA) has long been associated with fertility (1-5). Endocrine tissues like the adrenal and pituitary gland as well as the theca interna, granulosa, follicular fluid, and the luteal compartment of the ovary accumulate high concentrations of AA (6-8). Ovarian vitamin C is an essential cofactor for the biosynthesis of collagen, that is required for the high rates of tissue remodeling that attend follicle growth, ovulation, and corpus luteum development (9-11). Consequently, scorbutic guinea pigs are anovulatory and show ovarian atrophy, marked degeneration of follicles, a failure of implantation, and an increase in spontaneous abortion (12). Synthesis and secretion of steroids, catecholamins, and neuroendocrine peptides appear to be ascorbate-dependent (13-15). However, the ascorbic acid of the ovary is under endocrine control and rapidly depleted by high levels of LH, ACTH (16,17), or Prostaglandin, a luteolytic agent. Luteal regression is associated with ascorbate depletion and the generation of reactive oxygen species, which inhibit the action of LH and block steroidogenesis (18,19). AA is the preeminent water-soluble antioxidant (20). Women with unexplained infertility have a lower total antioxidant status in their peritoneal fluid (21). In animal studies AA was shown to inhibit follicular apoptosis (22) and to protect ovarian cells from...