Most MS Drugs Safe in Pregnancy, One May Raise Birth Defect Risk

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Key Takeaway

Most MS medicines taken before or during pregnancy were not linked to childhood developmental disorders, but one drug type (S1PR modulators) may raise the chance of birth defects and needs more study.

What They Found

Researchers looked at 1,374 children born to mothers with MS and followed them for about 7.5 years on average. They found no clear link between mothers taking disease-modifying therapies (DMTs) in pregnancy and children developing neurodevelopmental disorders (these are delays or differences in how a child learns, talks, or moves). Looking at major congenital anomalies (serious birth defects present at birth) in 1,252 children with at least 2 years of follow-up, 3.9% had such anomalies, which is similar to general population rates. Children whose mothers had taken S1PR modulators (a specific type of MS drug that affects immune cells) showed a higher percentage of birth defects (8%), but the group was small so the estimate is uncertain. Because the number of pregnancies exposed to S1PR drugs was small, the study could not be sure if the higher rate is real; the authors say larger studies are needed to confirm this finding.

Who Should Care and Why

Pregnant people with MS and those planning pregnancy should care because medicine choices before and during pregnancy can affect a baby's health; this study suggests most common MS drugs did not raise the risk of developmental disorders. Caregivers and family members should know that regular monitoring and discussion with a neurologist and obstetrician are important, especially if a mother took or is taking S1PR modulators. Healthcare providers should use this information as one piece of the decision-making puzzle—balancing relapse risk in the mother with possible risks to the baby. Think of treatment decisions like tuning a radio: you want to keep the mother’s MS under control (a clear signal) while avoiding static (risks to the baby); this study helps identify which stations might cause static. People who were exposed to S1PR drugs in pregnancy or are considering them should have a detailed risk discussion and possibly extra prenatal screening.

Important Considerations

This was an observational, historical study, so it can show associations but not prove cause-and-effect; other unmeasured factors might have influenced results. The number of pregnancies exposed to S1PR modulators was small, making the estimate for birth defects less certain and more likely to change with larger studies. The authors call for bigger, prospective (planned forward-looking) studies to confirm whether S1PR modulators truly increase birth defect risk before changing treatment rules.

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MS Genetics Clinical Trials Caregivers

Whether you’ve recently been diagnosed with Multiple Sclerosis (MS) or are seeking to broaden your understanding of this complex, neurodegenerative disease, navigating the latest research can feel overwhelming. Studies published in respected medical journals like Clinical pharmacology and therapeutics often range from early-stage, exploratory work to advanced clinical trials. These evidence-based findings help shape new disease-modifying therapies, guide symptom management techniques, and deepen our knowledge of MS progression.

However, not all research is created equal. Some clinical research studies may have smaller sample sizes, evolving methodologies, or limitations that warrant careful interpretation. For a more comprehensive, accurate understanding, we recommend reviewing the original source material—accessible via the More Details section above—and consulting with healthcare professionals who specialize in MS care.

By presenting a wide range of MS-focused studies—spanning cutting-edge treatments, emerging therapies, and established best practices—we aim to empower patients, caregivers, and clinicians to stay informed and make well-informed decisions when managing Multiple Sclerosis.

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