Avonex and Pregnancy

Hi all, hope everyone is well.

I have a question, which not even my GP could help me with, so wondered if anyone on here had any advice or experience.

I have been injecting Avonex since March, and have just found out that I am pregnant. I have been taking the pill, so a pregnancy was the last thing I was expecting.

What I need to know is does Avonex effect my unborn baby. Because of being on the pill, I am not sure how pregnant I am but the doctor says I’m still under 12 weeks.

My partner & I have a big decision to make, and the effect of Avonex on my baby is a main contribution to that decision.

Any help greatly received, many thanks Andrea xx

There was a paper published recently (Lu et al, 2011) that said that although MSers who became pregnant whilst on interferon were more likely to need an assisted delivery, the babies were fine. All the mums in the study stopped the interferon within 2 months.

There is another paper (Amato et al, 2010) that found that mums on interferon had smaller babies, but that they were normal on all measures by 2 years of age. These mums stopped the interferon by about 5 weeks though.

I found another one that said smaller birth weight, but everything else OK (Patti et al, 2008), but the abstract doesn’t state how long the mums were on interferon.

So, there is evidence that there are no lasting effects if the interferon is stopped within a couple of months. 12 weeks looks like it’s a bit of an unknown though and there’s a lot going on during those 4 weeks.

What does your neuro think?

Very best of luck with making your decision.

Karen x

As far as I know, the reason they tell you to avoid pregnancy while taking Avonex is because they cannot guarantee that it is safe for a developing baby, rather than that they know it to be harmful. So it is a safety first thing, rather than fear of some specific problem. There have certainly been stories on here from people in your position who have had a perfectly normal pregancy and a healthy baby at the end of it.

But it’s an expert opinion you need, obviously, and I think you should insist on a chat with your neurologist, by phone if necessary, so he/she can put your minds at rest before the holidays. At the same time you might want to give the Biogen helpline number a ring and talk to one of their nurses (who are very helpful, in my experience although it was something different I talked to them about.). I am sure they will be able to advise/reassure you and they will certainly be familiar with this situation.

Congratulations, by the way!



Hi congratulations on your pregnancy. I took betaferon until I could confirm my pregnancy with a test (so about 5 weeks) . I did this with both pregnancies and I now have a 10 year old and a 6 (7 on Friday) year old. No problems either during pregnancies or with the children afterwards. My son was a ventouse delivery in a great panic because he had the cord twice around his neck. Don’t think this was anything to do with the betaferon, my daughter was a normal delivery. Weighed 6lb 6 and 7lb 2 respectively. My son is quite big for his age now and my daughter is just about the smallest in her class, at dancing, trampoline etc but again I don’t think this is related to betaferon ad she is not abnormally small. I am on the small side myself. Cheryl:)