That was the key finding from a study conducted by researchers at Iran's Avicenna Research Institute and the University of Kentucky.
Ovulation induction has been shown to cause oxidative stress during the intracytoplasmic sperm injection (ICSI) treatment cycle, and women with polycystic ovarian syndrome (PCOS) are more prone to oxidative stress.
However, it was not clear which antioxidant supplements, if any, might help reduce oxidative stress in these women. As such, the researchers conducted a trial to determine the effects of combined vitamin D and E supplementation on ICSI results involving women with PCOS.
They recruited 105 infertile PCOS patients who had been scheduled for ICSI and assigned them to either a treatment group or a placebo group.
Each member of the treatment group received 400mg of vitamin E a day and 50,000 IU of vitamin D3 every fortnight for eight weeks.
Afterwards, the researchers observed that "pregnancy, clinical pregnancy and implantation rate were significantly higher in (the) treatment group".
However, they added that though there was a positive association between vitamin D level, implantation rate and increased clinical pregnancy, it was unclear if this as due to its antioxidant mechanism.
Furthermore, "no significant association was detected between either follicular fluid or serum Malondialdehyde and total antioxidant capacity and ICSI outcomes".
They also said that despite vitamins D3 and E being possibly crucial in reproductive physiology, there was insufficient evidence to prove the positive impact of "adjuvant consumption of these vitamins in the treatment outcomes of infertile PCOS women", at least in terms of antioxidant activity.
More research needed
They wrote that the trial's results did not manage to provide clinical evidence of the efficacy of vitamins' antioxidant properties in the success rate of IVF.
They concluded that though the treatment group experienced an improved rate of pregnancy, their data showed that "such (an) outcome is not due to an antioxidant mechanism".
"Clearly, more research is needed to further elucidate the possible mechanistic pathways by which these micronutrients act, and whether different doses result in different outcomes."
Source: Clinical Nutrition ESPEN
"Role of vitamin E and D3 supplementation in Intra-Cytoplasmic Sperm Injection outcomes of women with polycystic ovarian syndrome: A double blinded randomized placebo-controlled trial"
Authors: Farnaz Fatemi, et al.