MS treatments and pregnancy
A new online survey has found that most people with MS don’t know if the medication they are taking is associated with a risk of birth defects (Rasmussen and colleagues. Mult Scler Relat Disord 2018;24:129-134). The survey involved 590 people with MS in Denmark. The average age of respondents was 40 years, and they’d been living with MS for 11 years. Overall, a majority of people said they felt they were well-informed about family planning issues, however, 42% of women and 74% of men said they weren’t aware of the effect of medications on the fetus.
The potential for MS medications to cause birth defects isn’t very well studied. Much of the information comes from animal studies, which isn’t entirely applicable to humans. The best method of determining risk is to track pregnancies that are carried to term after exposure to a drug, but this isn’t ideal for mother or baby. Proper scientific studies can’t be done because it wouldn’t be ethical to expose pregnant women to potentially harmful drugs.
Whether an MS medication has the potential to harm the baby is somewhat beside the point since most people would prefer to be drug-free during pregnancy and breast-feeding. So a rule of thumb is to avoid pregnancy while taking an MS medication. This applies to men as well since some MS medications can affect sperm quality – a precaution that many neurologists fail to mention, according to the Danish survey.
The survey also found that 50% of women and men would like to have children, with 25% of women and 16% of men saying that they’d like to start a family within the next two years.
If that is the plan, a little bit of scheduling will be needed to ensure that everything goes well. The best approach is to discuss your pregnancy plans with your neurologist and MS nurse. If a pregnancy is planned at some point in the next six months, it may be best to delay starting a therapy until after the baby is born (depending on how severe you MS is now). If a pregnancy is planned in a year or two, you can start a medication with the view to stopping once you actively start trying to get pregnant. Some medications can be taken right up until you become pregnant (e.g. Copaxone, interferons, Tecfidera) with minimal risk to the baby.
Other drugs take more time to wash out of your system, so they should be stopped a few weeks or months before you actively try to get pregnant. For example, it’s important to avoid pregnancy for at least two months after your last dose of Gilenya, four months after your last infusion of Lemtrada, and six months after your last dose of Mavenclad or Ocrevus.
If your MS is especially severe, your doctor may advise you to continue taking a medication during pregnancy to avoid worsening of your MS. Whether or not you stay on treatment will be up to you – it’s your body, your baby and your decision. There is a slightly higher risk of having a relapse after the baby is born, so doctors often advise people with very active MS to go back on treatment as soon as possible. In this scenario, since medications should generally be avoided while breast-feeding, you’ll need to weigh the pros and cons. If you go back on treatment, you’ll need to switch to bottle feeding earlier. If you prefer to breast feed, you’ll have a higher risk of having a relapse while you remain untreated.
Pregnancy planning is essential to avoid nine months of worrying about whether your baby was exposed to your medication and whether that exposure will have an effect. This issue was highlighted in the Danish survey. One in 10 women said they’d had an unplanned pregnancy while on an MS medication. Due to concerns about potential harm to the fetus, 49% of women subsequently opted to have an abortion.
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