A Reversible Type of Male Infertility?

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One potential contributor that doesn’t receive enough attention is a drug used for two different reasons: It was first approved to shrink enlarged prostates, but is now also used to treat male pattern baldness. Called finasteride, the drug works by decreasing levels of a natural body hormone (DHT). This decreases growth of the prostate and can also increase hair regrowth or slow hair loss.²

Given that many men of reproductive age may be using finasteride to slow hair loss, researchers felt its impact on fertility deserved closer scrutiny. Published in Fertility and Sterility, their large 2013 study found that finasteride could reduce sperm counts in some men, even at low doses.³ The researchers examined a pool of 4,400 men being evaluated at an infertility clinic from 2008 to 2012. Among these patients, 0.6 percent were on finasteride for an average of 57.4 months and on an average dose of 1.04 mg a day.

Here’s the kicker: After discontinuing use of finasteride, sperm counts increased on average nearly 11.6 fold. The results were particularly pronounced in men with a low concentration of sperm in their semen (severe oligospermia) during the initial assessment. Although their degree of recovery was variable, no man experienced a decrease in sperm count after stopping the drug. In addition, there were no changes in hormone levels or in sperm shape (morphology) or the ability of sperm to move properly (motility).

Given these results, the researchers recommend that subfertile men discontinue use of finasteride and that men who want to have children use it with caution. They suggest that patients may not see the full return of normal semen parameters until they have been off the medication for 2 to 3 months. Stopping the drug may not necessarily allow for a spontaneous pregnancy, they said, but it might allow for a less invasive type of fertility therapy.

Minoxidil is another medication used to treat both female and male hair loss. Evidence linking this medication to reductions in sperm count is lacking.

Sources

1. American Society for Reproductive Medicine: Quick Facts About Infertility.
2. WebMD: Propecia.
3. Samplaski MK et al. Fertil Steril. 2013;100:1542–1546.

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