New info on MS and pregnancy – ECTRIMS 2019

Highlights from the 35th congress of the European Committee for Treatment and Research in MS (ECTRIMS), September 11-13, 2019.  Several new studies have provided important new information about pregnancy and MS and/or updated what was previously known. All studies were presented at the annual meeting of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS). Here is a wrap-up of some of the key questions addressed by the new research.

When should I try to become pregnant?

About 1 in 3 women become pregnant after being diagnosed with MS. But the timing of the pregnancy is important. MS needs to be treated, but it’s best not to be taking a medication during pregnancy. The conventional wisdom is to start a medication to control the MS (to avoid relapses during the pregnancy and after childbirth) with the plan to stop the drug when you start actively trying to become pregnant. A new study provides support for this strategy (Portaccio and colleagues. ECTRIMS 2019; abstract P410). The researchers looked at 330 women who became pregnant over a 6-year period. They found that women had a 40% higher risk of developing disability if they had more relapses in the year before getting pregnant. This means that you’ll be better off over the long term if you can get your MS under control for a year before becoming pregnant.

Will fertility treatments affect my MS?

MS generally doesn’t affect a woman’s fertility, but about 1% of women with MS do use what is called an “assisted reproductive technology” (ART, such as in vitro fertilization) to become pregnant. Hormones are believed to affect MS and a number of studies have found that the hormone treatments used during fertility treatment increase the likelihood of having a relapse (Bove and colleagues. Mult Scler 2019; epublished August 1, 2019). The PREG-MS study at Harvard agrees, somewhat (Manieri and colleagues. ECTRIMS 2019; abstract P1150). It found that 10% of women had a relapse during pregnancy, but this rate was four times higher (44%) in women who received a fertility treatment. This may indicate that fertility treatments increase the risk of relapses. Or it may mean that the women stopped taking their MS medication for a prolonged period during this process and that’s what put them at higher risk of a relapse.

Is pregnancy “protective”?

There are contradictory findings on whether women with MS who become pregnant are less likely to develop disability later on: some studies say pregnancy protects against disability, some say it has no effect on disability (Jokubaitis and colleagues. Ann Neurol 2016;80:89-100. Bsteh and colleagues. PLoS One 2016;11:e0158978). Another way of tackling the question is to look at women who never become pregnant (Zeydan and colleagues. ECTRIMS 2019; abstract P1141). A small study at the Mayo Clinic found that women who never became pregnant developed secondary-progressive MS at an earlier age (average age 40 years) compared to those who had children (average age 47 years). So this suggests that pregnancy had some effect on the course of MS.

Will MS (or MS medications) affect the baby?

An analysis of the Swedish MS Registry found that women with MS were somewhat more likely to have a baby that is born early or with a lower birth weight compared to women without MS (Razaz and colleagues. ECTRIMS 2019; abstract P778).

There was no increased risk of pregnancy complications if a woman was exposed to an MS medication during pregnancy. There was a slightly higher risk of birth defects (5% compared to 3% with no drug exposure). But it’s important to know that these risks differ depending on the MS medication you take.

According to the recent UK guidelines, some medications (Copaxone, interferons, Tecfidera) can be taken right up until pregnancy (Dobson and colleagues. Pract Neurol 2019;19:106-114; free full article at In some cases, a few medications can be taken during pregnancy (e.g. Copaxone, interferons, Tysabri), if needed. Tysabri should generally be stopped before the third trimester. Some medications (Aubagio, Ocrevus, Gilenya, Mavenclad, Lemtrada) should not be taken during pregnancy. In some cases the timing will be important: you can start trying to conceive about 2 months after stopping Gilenya, 4 months after the last dose of Lemtrada, 6 months after the last dose of Mavenclad or 12 months after the last dose of Ocrevus (Dobson 2019). Some treatments can be considered during breastfeeding (e.g. Copaxone, interferons, Tysabri), although most (Aubagio, Tecfidera, Gilenya, Ocrevus, Mavenclad, Lemtrada) should not be taken if you are breastfeeding. The decision to breastfeed, or how long, will depend on your personal preferences and how active is your MS. All of this information can be confusing, but your neurologist or MS nurse can guide you through the Do’s and Don’ts of MS drugs during and after pregnancy to help you ensure the health of mother and baby.

(Type “pregnancy” in the Search box on for more on this topic.)

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