Abstract
BACKGROUND: Randomized clinical trials show that men's use of antioxidant supplements during infertility treatment may improve clinical outcomes. However, important limitations in the design of most trials make it difficult to draw firm conclusions on their findings. OBJECTIVE: We examined whether men's intake of antioxidants and biologically related compounds without direct antioxidant capacity is associated with outcomes of assisted reproductive technologies (ARTs). METHODS: We conducted a prospective cohort study of men in couples who underwent infertility treatment with ART using their own gametes between 2007 and 2017. We followed 171 couples who presented at Massachusetts General Hospital Fertility Center and underwent 294 autologous ART cycles for infertility treatment. Diet was assessed in both partners using an FFQ. The primary study outcome was the probability of achieving a live birth as a result of infertility treatment. Secondary outcomes were fertilization, implantation, and clinical pregnancy rates. Generalized linear mixed models with random intercepts were fitted to account for multiple ART cycles per woman while adjusting for confounding. RESULTS: Men's vitamin C intake was positively associated with fertilization rate. The adjusted fertilization rate (95% CI) for couples in the lowest and highest quartiles of men's vitamin C intake were 69% (61-76%) and 81% (74-86%) (P-trend = 0.02). Men's β-carotene intake was positively associated with fertilization rate in intracytoplasmic sperm injection cycles but not in conventional in vitro fertilization cycles (P-interaction = 0.01). Men's α-carotene intake was inversely related to the probability of live birth. The adjusted probabilities of live birth for men in the lowest and highest quartiles of α-carotene intake were 43% (28-60%) and 22% (12-36%), respectively. CONCLUSIONS: Men's intake of vitamin C and β-carotene is positively related to fertilization rate but this does not translate into higher pregnancy or live birth rates in couples undergoing infertility treatment.