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EB Research - Reproductive Epidemiology

Folic Acid and Zinc Supplementation Trial (FAZST)

Study Objective

The primary objective of the study is to assess the efficacy of folic acid and zinc supplementation in males on semen quality and fertility treatment outcomes (i.e., live birth rate) among couples seeking fertility treatment. A double-blind, placebo-controlled randomized trial of folic acid and zinc supplementation will be conducted. Following a screening/randomization visit, participants will return at baseline, 2, 4, and 6 months.


Infertility affects 10 to 15% of couples attempting to conceive. Male factor subfertility plays a role in about 50% of subfertile couples, with largely unknown etiology. An intervention with even a small absolute effect on any component of male factor infertility has tremendous implications at the population level because of the large potential attributable benefit. Two micronutrients fundamental to the process of spermatogenesis, folate and zinc, are of particular interest as they offer a potential low cost and widely available treatment. Though the evidence has been inconsistent, small randomized trials and observational studies show that folate and zinc have biologically plausible effects on spermatogenesis and improved semen parameters. These results support the potential benefits of folate on spermatogenesis, and suggest that supplementation with folate and zinc may improve semen quality, and perhaps, assisted reproductive technology (ART) outcomes.

Study Design & Progress

This is a multi-center, double-blind, randomized placebo-controlled trial to assess the effects of folic acid and zinc dietary supplementation on semen quality , and indirectly on conception rates and pregnancy outcomes among 2400 male partners of couples seeking assisted reproduction. A total of 2,400 male participants will be randomized equally (1:1) either to active study dietary supplements (folic acid and zinc daily) or to matching placebo. Only the males will be randomized to study dietary supplement or placebo. Treatment will continue for 6 months. Following a screening visit, participants will return at baseline, 2, 4, and 6 months. The trial is ongoing and currently recruiting with expected completion in 2017. NCT Clinical Number: NCT01857310

Principal Investigators

Enrique F. Schisterman, Ph.D. & Sunni L. Mumford, Ph.D.

DIPHR Collaborators

Last Reviewed: 09/09/2014

Contact Information

Name: Dr Enrique Fabian Schisterman
Chief and Senior Investigator
Epidemiology Branch
Phone: 301-435-6893
Fax: 301-402-2084

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