Pregnancy Poses Challenges to MS Management, Review Study Shows
Women with multiple sclerosis (MS) who receive high-efficacy disease-modifying therapies (DMTs) before conception have a greater risk of relapses and disability progression during pregnancy than those given moderate-efficacy or no DMTs, according to a systematic review of studies.
Exclusive breastfeeding for at least two to four months, however, was associated with a significantly lower risk of relapses after delivery.
The findings suggest that a decision regarding DMT use “before, during, and after pregnancy for treating MS remains difficult,” the researchers wrote, adding that “treatment decisions need to be taken by the patient and healthcare professional after careful consideration of all of the potential benefits and risks.”
The study, “A systematic review of relapse rates during pregnancy and postpartum in patients with relapsing multiple sclerosis,” was published in the journal Therapeutic Advances in Neurological Disorders.
MS is the most common neurologic condition in women of reproductive age, but women wanting to conceive are usually advised to discontinue their DMTs, despite evidence demonstrating that stopping DMTs increases the risk of relapse during and after pregnancy.
Recently, the European Medicines Agency allowed the use of some DMTs — namely interferon betas — during pregnancy and breastfeeding, after extensive research demonstrated that these do not raise the risk of adverse pregnancy outcomes. But whether these remain safe beyond the third trimester remains unknown.
In addition to decisions about stopping or not stopping their DMTs, women are faced with several other decisions, such as when to resume DMTs after delivery and whether to forgo breastfeeding. But the “best strategy to reduce the rate of relapse during and after pregnancy remains up for deliberation,” the researchers wrote.
To help clinicians and patients make informed decisions about MS management during pregnancy, researchers in Germany and EMD Serono (known as Merck KGaA outside the U.S. and Canada) reviewed published studies examining disease outcomes in women before, during, and after pregnancy, along with DMT use during these periods.
Among the 469 studies identified in two databases, 28 were included in the analysis, totaling 5,324 pregnancies in 4,739 patients.
A total of five studies assessed the impact of DMT use before conception on relapses during pregnancy. All found that patients receiving high-efficacy DMTs — mainly Tysabri (natalizumab) and Gilenya (fingolimod) — had a greater risk of relapse during pregnancy compared with patients on moderate-efficacy DMTs (mainly interferon beta or Copaxone, or glatiramer acetate) or no DMT.
The use of high-efficacy DMTs was also associated with a greater risk of disability worsening, as assessed with the expanded disability status scale (EDSS).
The findings may be attributed to an underlying higher disease activity among those high-efficacy medications, but also to the longer washout periods recommended for high-efficacy DMTs before pregnancy, the researchers noted.
Women who continued to use DMTs during early pregnancy, namely in the first trimester, had a reduction in relapses compared with those who discontinued treatment.
Of the 28 studies, 21 included data on relapses that occurred postpartum in women treated with DMTs at varying times throughout pregnancy. Overall, 1,841 pregnancies were exposed to DMTs before conception, 594 during pregnancy (ranges from six weeks to entire pregnancy), and 1,004 in the postpartum period.
In general, exposure to DMTs before conception had no impact on relapses one year postpartum, compared with no DMTs. However, use of high-efficacy DMTs before conception was associated with a twofold higher risk of postpartum relapse, compared with other DMTs.
In four of seven studies, exposure to DMTs during pregnancy (mainly the first trimester) was associated with fewer postpartum relapses versus no DMT exposure. The other three studies found no differences.
Among the eight studies assessing the role of breastfeeding on relapses, six showed that exclusive breastfeeding (no formula supplementation for at least two months) reduced the risk of postpartum relapse compared with nonexclusive or no breastfeeding.
When exclusive and nonexclusive breastfeeding were examined as a group, however, results showed no effects on postpartum relapse rates compared with no breastfeeding.
Overall, “results of this systematic review concerning women with relapsing MS show a complex and often conflicting picture regarding DMT exposure and relapses during and after pregnancy,” the researchers wrote.
“Although our data are limited by variability between studies, there is some evidence suggesting the use of natalizumab or fingolimod preconception is associated with increased risk of relapses during pregnancy, highlighting the need for effective disease-management strategies in these especially high-risk patients,” they concluded.