“Could Breastfeeding Hold the Clue to a Future MS Treatment?”

How a Natural Post-Pregnancy Change Might Inspire the Next Generation of Therapies

Every year, thousands of women living with multiple sclerosis (MS) notice something remarkable: after giving birth, their MS flare-ups often quieten down while they’re breastfeeding.
In fact, studies show that women who breastfeed are around 50% less likely to have an MS relapse compared to those who don’t (Fleischmann et al., 2020).

But why?

For years, scientists assumed it was all about hormones, changes in oestrogen or prolactin protecting the brain (Morrison et al., 2006). But we asked; what if that’s only part of the story? What if the real key lies not in hormones, but in the way, breastfeeding reshapes the immune system. Could we recreate that effect in everyone, even outside of motherhood?

Why Does MS Affect More Women Than Men?

Multiple sclerosis disproportionately affects women — around three times more often than men. Researchers believe this difference is linked to how the female immune system is naturally more reactive, designed to protect both mother and baby during reproduction (Voskuhl, 2020).
While this heightened immune activity is helpful for fighting infection, it can also make women more prone to autoimmune diseases like MS, where the immune system mistakenly targets the body’s own cells (Bove and Chitnis, 2014).
This makes the immune “quieting” effect seen during breastfeeding especially fascinating — it shows that the same system that can overreact can also self-regulate under the right biological conditions (Sellner et al., 2011).
Our proposed therapy builds on this idea, recreating that natural balance without relying on hormones.

From Baby Bottles to Breakthroughs

When we dug into the research, one molecule stood out among the rest: interleukin-6 (IL-6). IL-6 acts as a kind of chemical messenger, telling the immune system when to switch into “attack mode.” In MS, IL-6 levels are often abnormally high, which in turn increases the severity of inflammation in the brain and spinal cord (Itorralba et al., 2025).

Here’s the fascinating part: IL-6 drops during breastfeeding. This shift helps the body stay calmer and more anti-inflammatory; and it might explain why flare-ups are rarer during this time.

Figure 1 Breastfeeding naturally reduces IL-6 levels, calming the immune system and protecting the brain from MS flare-ups

So, our team wondered….

  1. Could we bottle this natural protective effect?

  2. Could we design a safe and effective treatment that mimics the effects of a low-IL-6 environment similar to breastfeeding?

A Novel Approach: Calming the Storm at Its Source

Our idea was simple but powerful: target IL-6 directly inside the brain.

Medicines designed to block IL-6 receptors already exist, drugs like Sarilumab and Tocilizumab, originally developed for rheumatoid arthritis. They’ve been used safely for years to calm inflammation elsewhere in the body (Nouri et al., 2020; Xu et al., 2021).

But MS is a brain-based disease, and there’s a major barrier in treating such diseases, specifically, the blood–brain barrier (BBB). A natural wall of tightly packed cells that keeps most drugs out of the brain (Wu et al., 2023). It’s like having a locked door between your medicine and its target.

So how do we unlock it?

Figure 2 This simple phrase captures the essence of our idea — using focused ultrasound to open the brain’s barriers so Sarilumab can step in, block inflammation, and help the brain repair itself.

The Clever Shortcut: Opening the Brain’s Door Gently

After reviewing several innovative technologies, one stood out as the safest and most effective for our purposes: Focused Ultrasound (FUS).

This technology uses harmless sound waves (much like those in medical scans) combined with microscopic bubbles to gently open the BBB for a few hours. This temporary “doorway” lets medication pass through safely and precisely where it’s needed, without surgery or lasting damage (Chen et al., 2022).

In our proposal, Sarilumab would be administered while FUS is applied to specific areas affected by MS inflammation. The antibody would cross into the brain, block IL-6 receptors, and calm the overactive immune cells attacking myelin.

Figure 3 This diagram illustrates our proposed non-hormonal treatment for MS during breastfeeding. Focused ultrasound gently opens the blood–brain barrier, allowing our Sarilumab antibodies to enter the brain and block IL-6 receptors. By preventing IL-6–driven inflammation, this approach mimics the natural immune protection seen during breastfeeding, helping reduce MS relapses safely and effectively.

This diagram shows how our proposed therapy, combining Sarilumab (an IL-6–blocking antibody) with Focused Ultrasound (FUS), could help reduce MS relapses during breastfeeding.

  1. Sarilumab in the bloodstream:

    These antibodies circulate through the blood but can’t normally reach the brain because of the blood–brain barrier — a tightly sealed protective wall that blocks large molecules.

  2. Focused Ultrasound:

    Low-intensity sound waves, used alongside microscopic bubbles, gently open the barrier for a short time. This temporary opening lets the antibodies pass safely into the brain without harm (Timbie et al., 2025; Song et al., 2018; Antoniou et al., 2024).

  3. Crossing into the brain:

    Once inside, Sarilumab binds to IL-6 receptors on immune and nerve cells.

  4. Blocking IL-6 signalling:

    By blocking these receptors, Sarilumab stops IL-6 from triggering inflammation — preventing immune cells from attacking the myelin sheath that protects neurons.

  5. The result — reduced inflammation:

    The brain becomes calmer and less reactive, much like the natural immune balance seen during breastfeeding when IL-6 levels drop. It’s science recreating what the body already does naturally — a gentler, smarter way to reduce MS flare-ups.

Figure 4 Exclusive breastfeeding for at least two months can reduce the risk of MS relapse by up to 70%. This infographic combines data from 2008–2023 studies showing how pregnancy and breastfeeding calm inflammation by lowering IL-6 levels, a natural process that inspired our proposed IL-6–targeted therapy for safer, non-hormonal MS treatment.

Why This Idea Matters

  • It’s non-hormonal. It avoids the complications of manipulating reproductive hormones and focuses purely on immune balance.

  • It builds on existing, proven drugs. Sarilumab is already licensed and well-studied, which makes this proposal more realistic than inventing a drug from scratch.

  • It uses cutting-edge but safe delivery. Focused ultrasound is already in human trials for Alzheimer’s and Parkinson’s, showing that this method can safely open the BBB in controlled settings (Zhang et al., 2020).

  • It mirrors nature. Instead of reinventing the wheel, it copies the body’s own protective mechanisms seen in breastfeeding.

Looking Ahead

What we’ve proposed is a treatment where a short, non-invasive ultrasound session could allow a targeted anti-inflammatory drug to reach the brain — calming MS symptoms while avoiding the major side effects of immune suppression. This approach could help new mothers with MS safely resume treatment after childbirth, but it might also open new doors for all patients, showing that inspiration for innovation can come from the most natural and everyday sources.

Reflection

Working on this idea reminded us that sometimes the answers to complex diseases are hidden in the body’s everyday miracles. Breastfeeding, something so natural and familiar, might hold the blueprint for a smarter, safer MS therapy. By studying how the immune system adapts during motherhood and combining that with new biomedical tools like focused ultrasound, we can transform ordinary biology into extraordinary science.

References

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Comments

Jack Devanny
22 days ago

The idea of combining IL-6 inhibition with focused ultrasound is creative, but I wonder if IL-6 alone captures the full protective effect of breastfeeding

Simon McGlynn
21 days ago

Oh, not at all. The overall effect of breastfeeding on the immune system is pretty extensive. We settled on IL-6 as what we wanted to target because, from our research at least, it seemed the safest choice and we felt that an abundance of caution was warranted when proposing treatments meant to pierce the BBB

Eva Kiely
15 days ago

This is a really creative way to tackle drug delivery to the brain - really interesting to read about! My one question however regards the use of IL-6 inhibition as a treatment mechanism. Inhibiting the immune response could potentially have adverse effects leading to patients becoming more prone to infections overall. Additionally is there a of infection to the brain while the "temporary doorway" created by FUS is open? Is it possible to dose this to purely reduce it's inflammatory effect rather than inhibiting the immune response completely?

Grace McCarthy
11 days ago

Thank you for your comment Eva, you have raised a really important point. IL-6 blockers can increase infection risk in some patients, but our idea isn’t about shutting down the immune system completely. The goal would be to bring IL-6 activity down to the calmer level we see naturally during breastfeeding, rather than wiping it out. With focused ultrasound helping the drug reach the brain more directly, the dose could be kept lower, which should reduce the impact on the rest of the immune system.

As for the “doorway” in the blood–brain barrier, focused ultrasound doesn’t create a physical hole. It just loosens the junctions between cells in a tiny, targeted area, and they tighten back up within a few hours. Current studies don’t show any increase in brain infections from this. Overall, the whole aim is to gently reduce harmful inflammation without switching off the body’s ability to fight infection.