July 10, 2014 | News | Living with MS MS Treatments

Fatherhood and MS medications

A great deal has been written about MS and pregnancy. The general rule of thumb is that women who plan to become pregnant should interrupt their MS medication, then resume treatment once the baby is born. (For more on this topic, see Is it Safe to Breastfeed, MSology, Aug. 23, 2012.) Many MS medications may be relatively safe during pregnancy, but most people would rather be drug-free and not take any chances.

But what about men? Should they stop treatment if they’re planning to father a child?

The areas of possible concern with MS medications is that they may affect the sperm either by altering the quality or quantity of sperm, transfer chemicals that could affect the fetus, or cause mutations.

As a general rule, the testes are protected from shifts in the immune response (they are “privileged” areas, at least to an immunologist). However, cells in the testes do have receptors that interact with the body’s own interferons; too much interferon signalling has been shown to contribute to infertility in mice (Satie and colleagues. J Biol Chem 2011;286:23280-23295). And there is one case report of a man with hepatitis C who was treated with an interferon drug (not the type of interferon used for MS) and an antiviral drug who showed sperm DNA damage (Pecou and colleagues. Fertil Steril 2009;91:e17-22).

So there is some suggestive evidence, but no hard data about the impact of MS medications on fathering a child.

Another way of examining this question is to look at real-life experience, and two new studies have done that. An analysis of databases in British Columbia compared babies born to men with MS on an injectable medication at conception compared to those not on a medication (Lu and colleagues. CNS Drugs 2014;28:475-482; presented at the ENS meeting in 2013). Of 195 babies born to men with MS, 41% were with fathers taking one of the interferons or Copaxone. Whether Dad was on a treatment or not at the time of conception had no impact on whether a baby was born prematurely or on the birth weight of the baby.

The second study looked at 78 pregnancies involving men on or off treatment at conception (Pecori and colleagues. BMC Neurol 2014;14:114; free full text at www.biomedcentral.com/content/pdf/1471-2377-14-114.pdf). Most men in the drug group were taking one of the interferons, but a few were taking Copaxone. In the drug-exposed group, there was one spontaneous abortion and three fetal complications, compared to four fetal complications (of which 2 resulted in abortions) in the non-exposed group. So medication use at conception had no effect on the rate of fetal complications. There was a higher number of maternal complications in the drug-exposed group, but this difference was not significant and is probably influenced more by maternal factors, such as the mother’s age, smoking and alcohol use during pregnancy, and so on.

The father’s medication use at conception also had no impact on the duration of pregnancy. However, the partners of the drug-exposed men were more likely to have a pre-term delivery at a rate that was higher compared to both the non-exposed group and the general population. There was a somewhat higher likelihood of a Caesarian section in partners of the drug-exposed group, but the rate was generally considered normal. Drug exposure had no impact on the baby’s weight or length at birth.

So the overall conclusion from these studies was that if a man is taking an interferon or Copaxone at the time of conception, there’s no apparent effect on the baby.

It’s important to note that these studies didn’t look at people taking other MS medications. There is no information on men taking Tysabri or Gilenya at the time of conception. There are some data to suggest that potent immunosuppressants, such as mitoxantrone (Novantrone) and cyclophosphamide (Cytoxan), can harm sperm (Cavalla and colleagues. Eurol Sci 2006;27:231-239). With Tecfidera (dimethyl fumarate), the testes are one of the main targets of the drug and animal studies have reported testicular toxicity (tissue shrinkage, inflammation, tumours) in mice, rats and dogs; it isn’t known if this is relevant in humans or to human fetuses. Aubagio (teriflunomide) can be detected in sperm, so it’s recommended that men stop taking the drug and undergo an accelerated elimination procedure to remove the drug from their systems before they try to conceive.

If you’d like to be drug-free at conception, it takes about 70 days for new sperm to become available, so that means you’d need to be off treatment for about 10 weeks. The exception is Aubagio, which takes a very long time to be eliminated from the body; with the accelerated elimination regimen, most of the drug can be removed in about 10 days, at which time you can start the 70-day clock to conception.

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